COBI_VMT_GHG_Emissions_Final_Report_August 2023
Sustainable
Transportation &
Greenhouse Gas
Emissions
Prepared for:
The City of Bainbridge Island
August 2023
Table of Contents
Background .................................................................................................................................... 5
Inventory Methodology ............................................................................................................... 7
VMT ................................................................................................................................................................................................... 7
StreetLight Data VMT ......................................................................................................................................................... 8
Transportation GHG Emissions ............................................................................................................................................... 9
On-Road Passenger & Freight Emissions .................................................................................................................. 9
Transit Emissions ................................................................................................................................................................11
Air Travel ...............................................................................................................................................................................12
Ferry Travel ...........................................................................................................................................................................12
Off-Road ................................................................................................................................................................................12
Total GHG Emissions ........................................................................................................................................................13
VMT & GHG Emissions Reduction Evaluation .......................................................................... 14
Travel Markets .............................................................................................................................................................................14
Validation Data ...................................................................................................................................................................17
Ferry Trips .............................................................................................................................................................................17
Employee Trips ...................................................................................................................................................................18
Remaining Ferry Trips ......................................................................................................................................................20
Resident and Non-Ferry Local Visitor Trips .............................................................................................................20
Travel Market Summary ..........................................................................................................................................................22
GHG Emissions Wedge Analysis ...........................................................................................................................................24
Sustainable Transportation Plan ............................................................................................... 30
Evaluation of Infrastructure Improvements .....................................................................................................................30
Safe Routes to School ..............................................................................................................................................................31
Total VMT Reduction ................................................................................................................................................................32
VMT and GHG Emissions Reduction Strategies ....................................................................... 33
Introduction ..................................................................................................................................................................................33
VMT Reduction Strategies ......................................................................................................................................................33
Key Takeaways ....................................................................................................................................................................35
Cost Comparison ...............................................................................................................................................................37
Impact of VMT Reduction Strategies .........................................................................................................................37
GHG Emissions Reduction ..............................................................................................................................................38
Recommendations .....................................................................................................................................................................40
Implementation ..........................................................................................................................................................................41
List of Figures
Figure 1: City of Bainbridge Island Climate Action Plan GHG Emissions Reduction Goals ..................................... 5
Figure 2: Input StreetLight Zones ............................................................................................................................................... 15
Figure 3: Average Daily Vehicle Trips & VMT (2021) .......................................................................................................... 16
Figure 4: Employee Vehicle Trips & VMT (2021) ................................................................................................................... 19
Figure 5: Employee Vehicle Trips by Trip Length .................................................................................................................. 20
Figure 6: Resident and Local Visitor Non-Work Vehicle Trips (2021) ........................................................................... 21
Figure 7: Resident Vehicle Trips by Trip Length .................................................................................................................... 22
Figure 8: Travel Market Summary ............................................................................................................................................... 23
Figure 9: Impact of state and federal policies and regional/industry plans ............................................................... 25
Figure 10: Transportation Emissions Under Business-as-Usual Scenario ................................................................... 27
Figure 11: Transportation Emissions under Projected Scenario ..................................................................................... 28
Figure 12: Designing Bicycle Facilities for All Ages and Abilities ................................................................................... 32
Figure 13: Estimated Daily VMT Reduction ............................................................................................................................. 38
Figure 14: Estimated GHG Emissions Reduction ................................................................................................................... 39
List of Tables
Table 1: City of Bainbridge Island Annual VMT ........................................................................................................................ 7
Table 2: City of Bainbridge Island 2021 Annual VMT (PSRC and StreetLight Data) ................................................... 8
Table 3: 2018 US Community Protocol Emissions Factors ................................................................................................... 9
Table 4: 2018 US Community Protocol Fuel Economy .......................................................................................................... 9
Table 5: PSREA Emissions Factors ............................................................................................................................................... 10
Table 6: PSREA Fuel Economy for Kitsap County .................................................................................................................. 10
Table 7: PSREA Vehicles by Fuel Type for Bainbridge Island ........................................................................................... 10
Table 8: On-road Passenger & Freight Emissions ................................................................................................................ 11
Table 9: Transit Emissions .............................................................................................................................................................. 11
Table 10: Seattle-Bainbridge Island Ferry Fuel Consumption .......................................................................................... 12
Table 11: City of Bainbridge Island Total Transportation Emissions ............................................................................. 13
Table 12: Change in Emissions vs. 2021 Under Business-as-Usual Scenario ............................................................. 26
Table 13: Change in Emissions vs. 2021 Under Projected Scenario .............................................................................. 26
Table 14: Existing Citywide Mode Share .................................................................................................................................. 30
Table 15: Existing and Future Multimodal Networks .......................................................................................................... 30
Table 16: Future Potential Citywide Mode Share (2035) ................................................................................................... 31
Table 17: VMT Reduction from STP Strategies ...................................................................................................................... 32
Table 18: Assumed Phasing of Strategies over Time .......................................................................................................... 34
Table 19: Cost per VMT Eliminated ............................................................................................................................................ 37
Table 20: Daily VMT Reduction from Strategies ................................................................................................................... 37
Table 21: Annual GHG Emissions Reduction (Share of Reduction by Strategy) ....................................................... 40
Table 22: Estimated Emissions Reduction as Compared to Climate Action Plan Goals ........................................ 40
Table 23: Recommended Implementation Actions for VMT Reduction Strategies ................................................ 42
5
Background
In 2020, Bainbridge Island adopted their first Climate Action Plan (CAP), which is a comprehensive
roadmap to reducing the City’s greenhouse gas emissions (GHG) and increasing the island’s resiliency
against climate change.1 The CAP outlines specific actions that the City and community should undertake,
and sets specific targets for GHG emissions reduction based on a 95% reduction from the 2014 baseline,
shown in Figure 1. Transportation, including on-road and off-road vehicles, air travel, and ferry travel,
contributed over a third of Bainbridge Island community emissions in 2018, making it the second-largest
contributor to the community’s greenhouse gas emissions.
Figure 1: City of Bainbridge Island Climate Action Plan GHG Emissions Reduction Goals
In alignment with CAP goals to reduce Vehicle Miles Traveled (VMT) and reduce drive-alone mode share,
the City completed a Sustainable Transportation Plan (STP) in 2022 to establish the long-range vision for
providing a transportation system (streets, transit, trails, etc.) that improves mobility and safety for all
1City of Bainbridge, Climate Action Plan, https://www.bainbridgewa.gov/DocumentCenter/View/14354/Final-Bainbridge-Island-
Climate-Action-Plan-November-12th-2020
6
users while respecting the character of neighborhoods and maintaining a climate resilient environment.2
Scenario 2, Connecting Centers, in the STP was adopted by City Council as the preferred implementation
plan.
Building on these recent plans completed by the City, Fehr & Peers has undertaken an analysis to
establish 2021 VMT and associated GHG emissions for the City of Bainbridge Island and measure the GHG
emissions reduction potential of the Connecting Centers scenario from the STP. Fehr & Peers’ work builds
on prior work completed by Cascadia Consulting Group that established a GHG inventory for the City of
Bainbridge Island for two representative years – 2014 and 2018. This report covers the methodology for
creating the 2021 VMT and GHG emissions inventory, and evaluation of different scenarios to determine
which strategies and transportation projects will provide substantial progress towards reducing GHG
emissions.
2 City of Bainbridge, Climate Action Plan, November 2020.
https://www.bainbridgewa.gov/DocumentCenter/View/15850/VISION_Sustainable-Transportation-Plan_20220204_reduced
7
Inventory Methodology
The scope of the 2021 inventory is limited to VMT and GHG emissions from on- and off-road
transportation sources that travel within Bainbridge Island’s city limits. Fehr & Peers coordinated with
Cascadia Consulting Group to confirm the methodologies used in the 2018 inventory to maintain
consistency in the 2021 update; any differences in methodology are explained in the sections below. 2021
is the base year for the updated inventory since it is the most recent year for which a full year of data is
available.
VMT
In the 2018 inventory, the Puget Sound Regional Council (PSRC) provided VMT (scaled to the City of
Bainbridge from Kitsap County totals) for passenger vehicles and medium and heavy trucks from the PSRC
trip-based travel demand model.3 This data, along with transit VMT (scaled down from annual Kitsap
Transit revenue miles), is shown in the first column of Table 1 below.
To provide a point of comparison between the previous inventory and this update, Fehr & Peers
coordinated with PSRC to analyze 2021 VMT from the updated PSRC model, shown in the third column of
Table 1 below. Kitsap Transit provided 2021 annual revenue miles, which were scaled to Bainbridge Island
by the same adjustment factor as the 2018 inventory for the 2021 transit VMT. This methodology assumes
that the proportion of Kitsap Transit trips serving Bainbridge Island remained consistent between 2018
and 2021.
Table 1: City of Bainbridge Island Annual VMT
Source 2018 VMT1 Updated 2018 VMT2 2021 VMT2
Passenger Vehicle 69,543,900 69,958,200 71,942,900
Medium Truck 2,993,800 2,492,600 2,569,200
Heavy Truck 708,100 243,300 253,600
Transit 397,600 397,600 389,200
Total 73,643,400 73,091,700 75,155,000
Notes: PSRC provided VMT data for passenger vehicles, medium- and heavy-duty trucks. Kitsap Transit provided annual vehicle revenue miles for transit. All VMT was scaled down from Kitsap County totals to the City of Bainbridge. 1. Source: 2018 Bainbridge Island GHG Inventory. 2. Source: PSRC trip-based model, 2022.
Overall, Bainbridge saw an increase in annual VMT between 2018 and 2021, with the bulk of the VMT
increase attributed to passenger vehicles. There was a large drop in heavy truck VMT between 2018 and
2021 because PSRC updated the methodology used to calculate heavy truck trips. PSRC acknowledged
that the 2018 data was based on best available data at the time and provided an updated 2018 dataset
based on the new methodology to compare against 2021, shown in the second column of Table 1.
3 PSRC Trip-Based Travel Model: https://www.psrc.org/trip-based-travel-model-4k
8
Because the transit VMT is calculated from Kitsap Transit data, it remains consistent between both 2018
VMT datasets.
The difference between the two 2018 VMT totals is less than 1%; for comparison purposes, the updated
2018 VMT shown in Table 1 will be used as the baseline since it represents the best available data.
Bainbridge Island’s CAP uses 2014 as the citywide baseline for their GHG mitigation goals, so slight
changes to the 2018 inventory did not impact the observed trend of GHG emissions for the city.
StreetLight Data VMT
For the 2021 inventory, Fehr & Peers explored new sources of data that the City could use to track VMT
changes and to provide more granular data than the PSRC model for on-road vehicles. StreetLight Data
was chosen for the ability to analyze VMT from custom geographies within the island, as well as provide
data from 2019 and 2021. The 2019 data was selected as a comparison against the 2018 inventory for a
pre-COVID-19 validation.4
StreetLight Data provides the origin and destination of all vehicle trips that start or end on Bainbridge
Island, so the VMT was calculated by multiplying the total vehicle trips by the average trip length
observed in the data. The trip length was adjusted to account for the portion of the trip that traveled on
Bainbridge roads. Table 2 shows the comparison between the 2021 VMT provided by PSRC and the 2021
VMT calculated from StreetLight Data.
Table 2: City of Bainbridge Island 2021 Annual VMT (PSRC and StreetLight Data)
2021 PSRC VMT 2021 StreetLight VMT
Passenger Vehicle 71,942,900 81,997,500
Source: Fehr & Peers, 2023.
The PSRC VMT is an estimate for Bainbridge Island scaled down from the VMT for all of Kitsap County in
the regional trip-based model, whereas the StreetLight Data VMT is an estimate based on observed
vehicle trip activity occurring on the island.5 Therefore, the higher VMT estimate from the StreetLight Data
is reasonable given the difference in data sources. By establishing the 2021 VMT inventory with
StreetLight Data, the City can continue to track VMT changes over time using “Big Data”. The benefits of
using Big Data to track VMT include:
• Big Data is updated more regularly, and includes the ability to select specific date periods or time
frames.
4 https://www.streetlightdata.com/
5 StreetLight Data combines Location-Based Services (LBS) data with machine learning algorithms to understand travel behavior
across the country. Each month, StreetLight Data processes approximately 40 billion anonymized location records from smart
phones and navigation devices in connected cars and trucks and uses machine learning to transform these records into
aggregated and normalized route-based travel patterns. Vehicle trips are created from the location records by starting a trip once
a device is traveling at a reasonable speed, snapping records to road network data to estimate the trip route, and establishing a
trip end once the device stops moving. Data is validated using permanent traffic counters and embedded sensors, and normalized
with multiple data sources, including parcel data, digital road network data, and census information to calculate vehicle volume
estimates.
9
• Provides a greater sample size than traditional count data.
• Provides flexibility for using custom geographies and zones instead of single location counts.
• Provides ability to track entire trip and understand origin-destination patterns on and off-island.
• Data is typically cheaper than collecting traditional counts.
Transportation GHG Emissions
GHG emissions are inventoried by multiplying annual activity data (e.g., VMT) by emission factors
(greenhouse gas emissions produced per mile traveled) and average fuel economy data. Emissions were
calculated for on-road passenger & freight, on-road transit, air travel, ferry travel, and off-road
transportation sources.
On-Road Passenger & Freight Emissions
In the 2014 and 2018 inventories, on-road passenger and freight emissions were calculated using
emissions factors and fuel economy from the US Community Protocol, shown in Table 3 and Table 4.6
Table 3: 2018 US Community Protocol Emissions Factors
Fuel Type Emissions Factors (g CO2/gallon)
Diesel 10,210
Propane 5,590
Gasoline 8,780
Source: Cascadia, 2018.
Table 4: 2018 US Community Protocol Fuel Economy
Vehicle Type Fuel Economy
Gasoline Car 23.8
Gasoline Medium Truck 9.33
Diesel Medium Truck 13.81
Diesel Light Truck 17.4
Diesel Heavy Truck 6.06
Transit Bus 4.88
Source: Cascadia, 2018.
The US Community Protocol default emissions data was the best available at the time of the 2018
inventory but does not reflect changes on a year-by-year basis. Therefore, the emissions were updated for
the 2021 GHG inventory using region-specific emissions data from the Puget Sound Regional Emissions
Analysis (PSREA) work that Cascadia completed in August 2022.7 The PSREA analysis calculated emissions
by vehicle type by applying the PSRC activity-based travel model data8 to the EPA’s Motor Vehicle
6 ICLEI, Greenhouse Gas Protocols, https://icleiusa.org/ghg-protocols/
7 Cascadia, King County Countywide Geographic GHG Emissions, https://your.kingcounty.gov/dnrp/climate/documents/2022/king-
county-geographic-ghg-emissions-inventory-and-wedge-report-09-2022.pdf
8 PSRC Activity-Based Travel Model: https://www.psrc.org/activity-based-travel-model-soundcast
10
Emission Simulator (MOVES) model for Kitsap, King, Snohomish, and Pierce County.9 The PSREA
emissions factors and fuel economy data used in this inventory are shown in Table 5 and Table 6.
Table 5: PSREA Emissions Factors
Fuel Type 2018 Emissions Factors (g CO2/gallon) 2021 Emissions Factors (g CO2/gallon)
Diesel 10,210 9,770
Propane 5,590 5,590
Gasoline 8,780 8,400
Electricity1 0.00053 0.00035
Source: Cascadia, 2022. Data derived from PSRC and MOVES model outputs. 1. Measured in MTCO2e/kW, and assumed that EVs use 0.3 kW/mi.
Table 6: PSREA Fuel Economy for Kitsap County
Vehicle Type 2018 Fuel Economy (miles per gallon) 2021 Fuel Economy (miles per gallon)
Gasoline Passenger Car 22.01 22.48
Gasoline Medium Truck 10.85 11.03
Diesel Medium Truck 11.83 12.02
Diesel Passenger Truck 25.67 26.22
Diesel Heavy Truck 5.19 5.28
Transit Bus 1 1
Source: Cascadia, 2022. Data derived from PSRC and MOVES model outputs.
The PSREA data includes county-level summaries for vehicle fuel types. The passenger vehicle data was
adjusted to account for a greater share of electric vehicles (EVs) registered in Bainbridge Island than
Kitsap County as a whole. This breakdown of vehicles by fuel type for 2018 and 2021 is shown in Table 7.
Table 7: PSREA Vehicles by Fuel Type for Bainbridge Island
Year Vehicle Type Gasoline Diesel EV
2018 Passenger Vehicle 97.4% 1.1% 1.5%
2021 Passenger Vehicle 95.9% 1.1% 3.0%
2018 & 2021 Medium Trucks 67.6% 32.3% 0.0%
2018 & 2021 Heavy Trucks 0.0% 100.0% 0.0%
Source: Fehr & Peers, 2023.
From the data in Table 5 - Table 7, on-road emissions for 2021, measured in metric tons of carbon
dioxide equivalent (MTCO2e) were calculated using the formula below:
9 EPA MOVES: https://www.epa.gov/moves
11
𝑉𝑉𝑉𝑉𝑉𝑉𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 𝑡𝑡𝑡𝑡𝑡𝑡𝑓𝑓 × 𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸 𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐸𝐸𝐹𝐹𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 𝑡𝑡𝑡𝑡𝑡𝑡𝑓𝑓 × 1𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹 𝐸𝐸𝐹𝐹𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 𝑡𝑡𝑡𝑡𝑡𝑡𝑓𝑓 × 10−6
For 2021 GHG emissions calculations, the activity data source is:
• StreetLight Data VMT was used for passenger vehicles (from Table 2)
• PSRC VMT was used for freight (from Table 1)
On-road GHG emissions were also re-calculated for 2018, using the new VMT data from Table 1, and the
PSREA emissions data from Table 5 - Table 7 to understand the impact of the new methodology on the
2018 inventory.
Table 8: On-road Passenger & Freight Emissions
Vehicle Type Updated 2018 Emissions (MTCO2e) 2021 Emissions (MTCO2e)
Passenger Vehicle 27,655 29,977
Medium Truck 2,058 1,997
Heavy Truck 479 470
Total 30,191 32,443
Source: Fehr & Peers, 2023.
Based on this updated information, on-road GHG emissions increased by about 10% between 2021 and
2018 because VMT increased for passenger vehicles and medium- and heavy-duty freight on Bainbridge
Island.
Transit Emissions
Kitsap Transit provided data on 2021 transit fuel consumption by fuel type (diesel/propane/gasoline).
Annual fuel consumption was scaled to Bainbridge Island based on the City’s population relative to Kitsap
County.10 PSREA emissions factors were then applied to fuel consumption for Kitsap County to calculate
total transit emissions. The results of this analysis are shown in Table 9.
Table 9: Transit Emissions
Fuel Type 2021 Kitsap Transit Annual Consumption (gallons) Emissions Factors (g CO2/gallon) 2021 Emissions (MTCO2e)
Diesel 39,187 10,210 383
Propane 18,492 5,590 100
Gasoline 14,357 8,780 121
Total 604
Source: Fehr & Peers, 2023.
10 Scaled by a factor of 0.05.
12
Air Travel
While air travel is not within City limits, emissions from Bainbridge Island residents flying in/out of Seattle
Tacoma Airport are a significant portion of overall transportation emissions, and therefore are included in
a GHG emissions inventory. Through the PSREA analysis, total emissions from air travel at Seattle Tacoma
Airport were allocated to individual jurisdictions by a scaling factor based on population.
The 2018 Bainbridge Island Greenhouse Gas Emissions Inventory determined that emissions from
Bainbridge Island residents’ air travel were 31,002 MTCO2e in 2018. For the 2021 inventory, air travel
emissions were determined by applying the percent change in total landings at Seattle Tacoma Airport
between 2018 and 2021.
Total landings decreased 14% by 2018 and 2021, falling from approximately 216,000 total landings in
2018 to approximately 185,000 total landings in 2021. Applying the 14% decrease in total landings to
2018 emissions results in 2021 emissions of 26,581 MTCO2e. The emissions factor for jet kerosene (9.75 kg
CO2/gal) was obtained from ClearPath.
Ferry Travel
Ferry emissions were determined by analyzing the change in fuel consumption between 2018 and 2021.
To calculate fuel consumption, the total cost of fuel for the Seattle-Bainbridge Island Ferry route in 2021
was divided by the average price of diesel per gallon for west coast states (excluding California) from the
U.S. Energy Information Administration, as shown in Table 10. Between 2018 and 2021, total fuel
consumption decreased by 25% due to fewer trips on the Seattle-Bainbridge Island Ferry route during
COVID-19.
Table 10: Seattle-Bainbridge Island Ferry Fuel Consumption
2018 2021
Total Fuel Cost $7,382,000 $5,771,000
Average Cost per Gallon $3.36 $3.48
Fuel Consumed (Gallons) 2,200,950 1,659,605
CO2 emissions factor (MT/MMBTu) 0.0739 0.0739
Source: Fehr & Peers, 2023.
The 2018 Bainbridge Island Greenhouse Gas Emissions Inventory determined that emissions from ferry
travel were 11,334 MTCO2e in 2018. Applying the same emissions factors to 2021 fuel consumption results
in total GHG emissions of 8,550 MTCO2e.
Off-Road
Off-road emissions (including emissions from agriculture, construction, lawn/gardening, and recreational
vehicles) were scaled from the 2018 Bainbridge Island Greenhouse Gas Emissions Inventory by the change
in the population on Bainbridge Island between 2018 and 2021.
13
The 2018 Bainbridge Island Greenhouse Gas Emissions Inventory determined that off-road emissions were
10,331 MTCO2e in 2018. Between 2018 and 2021, Bainbridge Island’s population increased by 2.1% from
24,060 to 24,556. Applying the 2.1% increase to 2018 emissions results in 2021 emissions of 10,544
MTCO2e.
Total GHG Emissions
Emissions are measured in MTCO2e and are shown in Table 11 below.
Table 11: City of Bainbridge Island Total Transportation Emissions
Source 2014 Emissions – Baseline (MTCO2e) 2018 Emissions (MTCO2e)
Updated 2018 Emissions (MTCO2e)
2021 Emissions (MTCO2e)
On-road Passenger & Freight 27,448 27,3301 30,1912 32,443
On-road Transit 590 781 781 604
Air Travel 24,023 31,002 31,002 26,581
Ferry Travel 14,051 11,334 11,334 8,550
Off-road 9,204 10,331 10,331 10,544
Total 75,316 80,778 83,639 78,723
1. Source: 2018 Inventory 2. Uses new 2018 VMT from PSRC, and PSREA emissions factors
Source: Fehr & Peers, 2022.
Since 2014, total transportation-related GHG emissions have been increasing on Bainbridge Island. In
2020, the COVID-19 pandemic severely restricted travel across all modes. Across the region, the transit
service was cut by all agencies, including Kitsap Transit and Washington State Ferries, and vehicle mode
share increased as travel demand began to rebound in late 2020 and into 2021. Because of these factors,
total GHG emissions for transportation on Bainbridge Island are less than 2018, primarily because of
reductions in air and ferry travel, but still represent an increase from the 2014 baseline.
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VMT & GHG Emissions Reduction
Evaluation
Travel Markets
To identify the most effective recommendations to reduce VMT and GHG emissions, Fehr & Peers
conducted a travel market assessment to identify the key travel markets for trips into and out of
Bainbridge Island. Understanding the travel markets helps to identify which trip types would be most
affected by VMT reduction strategies and projects. Fehr & Peers used StreetLight Data to understand the
origin-destination patterns of the following travel markets:
• Residents
• Employees
• Local visitors (non-ferry trips)
• Ferry visitors & thru-travel
City staff provided input on defining the input geographic zones used in StreetLight’s origin-destination
analysis, shown in Figure 2 (one additional zone was drawn around the Seattle Ferry Terminal).
15
Figure 2: Input StreetLight Zones
16
Fehr & Peers summarized the average total weekday vehicle trips on Bainbridge Island using Tuesday,
Wednesday, and Thursday as representative days from 2021 for each zone shown in Figure 2. Leveraging
the origin-destination data for each zone, Fehr & Peers calculated total VMT by multiplying the average
trip length from a zone by the total average vehicle volume. Figure 3 breaks out vehicle trips and VMT on
Bainbridge Island based on their start and end location, where internal-internal trips start and end on
Bainbridge Island, external-internal trips either start or end on Bainbridge Island, and external-external
trips are visitor thru-trips to/from the ferry that pass-through Bainbridge Island.
The majority of vehicle trips on Bainbridge Island are short distance internal-internal trips; internal-internal
trips are almost 70% of total trips but contribute to less than 50% of total VMT. Moreover, XI/IX trips are
the greatest contributor to total VMT as the average trip length is much longer than most internal trips.
Figure 3: Average Daily Vehicle Trips & VMT (2021)
0
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II XI/IX XX Total
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Validation Data
To create the City’s travel markets from the StreetLight origin-destination data, multiple datasets were
referenced, including:
• American Community Survey (ACS) 2021 Population and Household Estimates11
• Longitudinal Employer-Household Dynamics (LEHD) OnTheMap Employment Data12
• Puget Sound Regional Council (PSRC) 2017-2019 Household Travel Survey13
• Washington State Ferry (WSF) Data
o Passenger Origin-Destination Survey14
o 2021 Seattle-Bainbridge Island Ridership Data15
The sections below describe the methodology used to create each travel market, and how the data
sources above were applied. The travel markets were analyzed in the order described below, using the
total trips shown in Figure 3. All vehicle trips from each subsequent travel market were subtracted from
the total. Therefore, the total vehicle trips are equal to the ferry trips + employee trips + resident trips +
local visitor trips.
Ferry Trips
Using the ferry zones defined in the StreetLight analysis, total vehicle trips to/from the Bainbridge Island
Ferry Terminal were scaled based on the average daily vehicle boarding data for the route from WSF’s
ridership data.
Ferry Thru-Travel
Ferry thru-trips are vehicle trips that take the Seattle-Bainbridge Island Ferry and have origins and
destinations outside of the city (e.g., travelers that get on the ferry in Seattle, get off on Bainbridge Island,
and continue on SR 305 to the Olympic Peninsula). These thru-trips are the sole contributor to external-
external vehicle trips for the city and were included in the city’s travel market inventory to understand the
portion of total VMT contributed by thru-travelers. The external-external VMT is less than 10% of the
average daily total, and because the City does not have control over this travel market, it will be
excluded from the VMT reduction evaluation.
Ferry thru-trips were identified by analyzing the origins and destinations of vehicle trips from both the
Bainbridge Island and Seattle Ferry Terminals. StreetLight characterizes a “trip end” when a device is
generally stationary for more than 5 minutes; therefore, all vehicle trips “end” at each ferry terminal.
Therefore, trips that start elsewhere in Kitsap County or on the Olympic Peninsula, and end at the
Bainbridge Island Ferry Terminal, are thru-trips that are destined for Seattle. The WSF Passenger Origin-
Destination Survey provided a calibration source, which summarized passenger survey origin-destination
data for the Seattle-Bainbridge Island route. The survey results indicated that about 30% of trips on the
11 https://data.census.gov/
12 https://lehd.ces.census.gov/applications/help/onthemap.html#!what_is_onthemap
13 https://www.psrc.org/our-work/household-travel-survey-program
14 https://wsdot.wa.gov/sites/default/files/2021-10/WSF-2013OriginDestinationSurvey-FullReport.pdf
15 https://wsdot.wa.gov/travel/washington-state-ferries/about-us/washington-state-ferries-planning/traffic-statistics
18
ferry route end outside of Bainbridge Island, a value used to factor the StreetLight data to normalize to
total vehicle volumes.
Local Ferry Travel
After subtracting the ferry thru-trips from the total ferry-related vehicle trips on Bainbridge Island, the
remaining vehicle trips were classified as “internal-internal”, since the trips start and end on the island. The
local ferry trips were then split out into resident, employee, and local visitor trips, which are described in
more detail in the following sections.
Employee Trips
Bainbridge Island has two unique components to their employee travel market: most people who live on
Bainbridge Island work elsewhere, and most employees who work on Bainbridge Island live elsewhere.
Therefore, these two populations were kept separate for analysis, and added together for total employee
trips and VMT.
Employment data from LEHD OnTheMap was used to identify where residents of Bainbridge Island work
(majority of residents worked in Seattle/Bellevue metro area, or on Bainbridge Island), and where
employees of Bainbridge Island live (majority of employees commuted from elsewhere in Kitsap County,
like Poulsbo or Silverdale).
For any employee with a job destination accessible by the Seattle-Bainbridge Island Ferry, a ferry terminal-
specific mode split was applied to understand the number of vehicle trips to the terminal each day. This
mode split was determined by the number of available parking spaces, Kitsap Transit ridership data, and
citywide mode share data from the PSRC Household Travel Survey. Then, the employee trips taken by
vehicle to/from the Bainbridge Island Ferry Terminal were subtracted from the local ferry trips, previously
calculated above.
All other employee trips pertained to employees that either lived and worked on Bainbridge Island, or
commuted from elsewhere in Kitsap County. Employee trips within Bainbridge Island or to the ferry
terminal were multiplied by the distribution of internal-internal trip lengths to get VMT. For employees
commuting from off-island, trips were multiplied by the average distance to the cities identified in the
LEHD data.
Figure 4 shows the total daily employee vehicle trips and associated VMT, and Figure 5 shows the
distribution of these trips by trip length. From Figure 4 and Figure 5, the bulk of employee VMT is due to
employees commuting from off-island.
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Figure 4: Employee Vehicle Trips & VMT (2021)
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Figure 5: Employee Vehicle Trips by Trip Length
Remaining Ferry Trips
After subtracting the ferry thru-trips and employee vehicle trips from the overall total vehicle trips
associated with the Bainbridge Ferry Terminal, the remaining trips were assumed to be from residents and
local visitors. WSF’s Passenger Origin-Destination Survey also includes information about trip purpose,
such as school trips and social/recreation trips. From this data, along with mode share information from
the PSRC Household Travel Survey for residents of Bainbridge Island, about 80% of the remaining ferry-
related vehicle trips could be attributed to residents (this includes pick-up/drop-off and parking at the
ferry terminal), and about 20% to visitors (many visitors do not bring their car onto the ferry, and
therefore are a much higher proportion of walk-on ferry passengers).
Resident and Non-Ferry Local Visitor Trips
After subtracting the leftover ferry trips from the total, all remaining vehicle trips are from residents and
local (Kitsap County) visitors. To analyze the trip split between residents and visitors, the PSRC Household
Travel Survey was used to understand both vehicle trip rates and trip length by trip purpose. The PSRC
data showed that on average, a person took approximately two non-work vehicle trips per day. This trip
rate was multiplied by the 2021 Bainbridge Island population to split out the resident non-work trips from
a combined non-work resident/visitor total. Figure 6 shows the breakdown of resident and local visitor
vehicle trips.
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Figure 6: Resident and Local Visitor Non-Work Vehicle Trips (2021)
The PSRC survey data was used to calibrate the trip lengths for the vehicle trips taken by residents and
visitors to/from Kitsap County. Since this travel market excludes work trips, Fehr & Peers filtered the trips
by trip purpose from the PSRC survey, and only included school, errand/shopping, and social/recreation
trips to/from Bainbridge Island. The trip length data was then used to calculate VMT for the resident and
local visitor travel market. Figure 7 shows resident (non-work) vehicle trips by trip length.
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Figure 7: Resident Vehicle Trips by Trip Length
As an additional source of validation, Fehr & Peers obtained average daily traffic (ADT) data from WSDOT
for the Agate Passage Bridge to calibrate the total number of XI/IX/XX trips to/from Bainbridge Island in
2021. The 2021 ADT was about 21,000, which is consistent with the sum of XI/IX/XX trips across all travel
markets.
Travel Market Summary
Figure 8 combines vehicle trips and associated VMT across all the city’s travel markets. This summary
identifies the travel markets that contribute the most to VMT, and subsequently, which travel
markets should be prioritized for VMT reduction strategies. The greater level of detail of the markets
and their impact on VMT informed the evaluation of potential VMT reduction strategies. For example,
strategies like teleworking would only influence employee VMT, whereas e-bike subsidies would most
impact resident VMT.
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Figure 8: Travel Market Summary
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GHG Emissions Wedge Analysis
New state and federal transportation-related legislation has been passed since GHG emissions were last
measured for the Island in 2018, including legislation targeted at reducing GHG emissions through
improved fuel standards, reduced fuel carbon intensity, and electrification targets. A “wedge analysis”
evaluated the impact of these policies on future transportation emissions in Bainbridge Island. The
analysis developed GHG emissions estimates under a “Business-as-Usual” scenario, where no action is
taken to reduce emissions, and a “Projected” scenario, that accounts for future emissions based on
implementation of Federal, State, Regional, and sector-specific policies.
The Business-as-Usual and Projected emissions scenarios were developed using the PSREA analysis
provided by Cascadia Consulting Group that forecasts future emissions for King, Kitsap, Pierce, and
Snohomish counties based on a 2014 baseline across five sectors – built environment, transportation and
other mobile sources, solid waste and wastewater, land use, and refrigerants.
The wedge analysis considers the following state and federal policies as well as industry specific plans that
are expected to impact GHG emissions from transportation sources:
• Federal Vehicle Regulations (CAFE standards) mandate improved fuel economy standards for
passenger cars and light trucks and require an industry-wide fleet average of approximately 49
mpg for passenger cars and light trucks by 2026.
• WA Clean Fuel Standard (HB 1091) requires a 20% reduction in carbon intensity of
transportation fuels by 2038 as compared to a 2017 baseline.
• WA Internal Combustion Engine Ban (SB 5974) establishes a target that 100% of new vehicle sales are electric by 2030.
• Because this is a current target, not a mandate, the PSREA work defined a more conversative approach, which assumes 65% of new vehicle sales are EV by 2030, and 100% by 2035.
• WA Climate Commitment Act (E2SSB 5126) places an economy-wide cap on carbon to meet the State’s GHG emissions reduction targets. The act impacts transportation emissions by
regulating transportation fuels.
• Air Transport Action Group 2050 Plan aims to achieve net zero aviation operations by 2050 through efforts that include technology advancements, infrastructure improvements, and
sustainable aviation fuels.
• Washington State Ferry (WSF) System Electrification Plan will electrify the WSF system, including the ferry between Bainbridge Island and Seattle, which is anticipated to be electrified by
2027.
• Puget Sound Regional Council (PSRC) Vision 2050 is the blueprint for the region’s transportation vision, programs, and infrastructure projects over the next 30 years and provides
future VMT estimates for the region.
The cumulative impact of each of these policies to reduce transportation emissions below the 2021
baseline of 80,000 MTCO2e is shown in Figure 9.
25
Figure 9: Impact of state and federal policies and regional/industry plans
PRSEA developed emissions estimates under “Business-as-Usual” and “Projected” scenarios for cities and
counties in the Puget Sound region through 2050. Fehr and Peers worked with Cascadia Consulting to
update the Kitsap County Business-as-Usual and Projected scenarios for Bainbridge Island using emissions
inventory data specific to Bainbridge for 2014, 2018, and 2021.
To determine future emissions for Bainbridge Island under the “Business-as-Usual” and “Projected”
scenarios, Fehr & Peers calculated the percentage change in emissions for Kitsap County for each
transportation subsector between 2021 and each horizon year, as shown in Table 12 and Table 13, and
applied that percentage change to the Bainbridge Island inventory.
26
Table 12: Change in Emissions vs. 2021 Under Business-as-Usual Scenario
Transportation Subsector
2021 Emissions (MTCO2e)1
2025 2030 2035 2040 2045
Pct Change MTCO2e Pct Change MTCO2e Pct Change MTCO2e Pct Change MTCO2e Pct Change MTCO2e
On-Road Vehicles 35,960 1% 36,600 3% 37,240 8% 39,030 13% 40,820 18% 42,580
Off-Road Equipment 10,540 1% 10,300 3% 10,480 8% 10,980 13% 11,480 18% 11,980
Aviation 26,580 1% 26,160 3% 26,610 8% 27,890 13% 29,170 18% 30,430
Ferries 8,550 1% 11,330 0% 11,330 0% 11,330 0% 11,330 0% 11,330
1. 2021 emissions under the business-as-usual scenario do not consider any improvements to fuel efficiency or electric vehicle adoption. Source: Fehr & Peers, 2023
Table 13: Change in Emissions vs. 2021 Under Projected Scenario
Transportation Subsector
2021 Emissions (MTCO2e)1
2025 2030 2035 2040 2045
Pct Change MTCO2e Pct Change MTCO2e Pct Change MTCO2e Pct Change MTCO2e Pct Change MTCO2e
On-Road Vehicles 33,050 -14% 27,860 -36% 20,180 -52% 14,530 -68% 8,660 -95% 4,120
Off-Road Equipment 10,090 -8% 8,980 -18% 8,010 -17% 8,040 -17% 8,040 -14% 8,380
Aviation 25,610 -6% 23,340 -14% 21,470 -19% 20,220 -24% 18,870 -30% 17,430
Ferries 7,780 10% 11,330 -95% 570 -95% 570 -95% 570 -95% 570
1. 2021 emissions under the projected scenario are slightly lower than emissions under the 2021 business-as-usual scenario because the projected scenario accounts for existing actions that reduce emissions, including improved fuel efficiency and electric vehicle adoption. Source: Fehr & Peers, 2023
Figure 10 illustrates future transportation emissions under the Business-as-Usual scenario.
27
Figure 10: Transportation Emissions Under Business-as-Usual Scenario
Under this scenario, emissions from on-road vehicles, aviation, and off-road equipment are all projected
to increase through 2045. The Business-as-Usual Scenario assumes that ferry service and fuel efficiency
remain fixed at 2018 levels, and as a result ferry emissions are projected to level off in 2025. A dip in
transportation emissions across all modes was observed in 2021 due to Covid-related declines in travel.
Figure 11 illustrates future transportation emissions under the Projected Scenario.
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Figure 11: Transportation Emissions under Projected Scenario
Under the Projected scenario, emissions from on-road vehicles, aviation, off-road equipment and ferries
are expected to fall below 2021 levels by 2025. Ferry emissions are projected to fall about 95% by 2030
with the expected electrification of the Bainbridge Island-Seattle Ferry in 2027.
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The decrease in emissions from on-road vehicles is driven by three factors, outlined below:
• Improved fuel economy: Fuel economy for gas- and diesel-powered passenger vehicles improves 25% between 2021 and 2045. Fuel economy for both gas- and diesel-powered freight vehicles also improves about 20% between 2021 and 2045.
• Cleaner fuel sources: Assumes a 30% reduction in CO2 emissions intensity for on-road fuel sources between 2021 and 2040.
• Electrification: Assumes about 85% of passenger vehicles are electric by 2045; electrified freight VMT increases from 5,000 miles in 2021 to 1.5M miles in 2050.
The decrease in emissions from off-road equipment is driven by the assumption that off-road
equipment (such as lawn equipment and construction) will also utilize cleaner fuel sources with a 30%
reduction in CO2 emissions intensity between 2021 and 2040.
The decrease in emissions from aviation is driven by two factors:
• Cleaner fuel sources: Assumes a 32% decarbonization of jet fuel and aviation gasoline by 2045
as compared to a 2021 Business-as-Usual Scenario.
• Innovation: Assumes a 16% reduction in jet fuel consumption by 2045 as compared to the 2045
Business-as-Usual Scenario from improvements in technology, operations, and infrastructure.16
The decrease in emissions from the ferry is driven by the assumption that the Bainbridge Island-Seattle
Ferry will be electrified by 2027. Consequently, GHG emissions from the ferry are projected to fall about
95% by 2030.
The wedge analysis shows that while federal and state policies will significantly reduce transportation-
related GHG emissions over the next 20 years, additional local efforts are needed to meet the City’s
emissions reduction target. Furthermore, these policies rely on aggressive electric vehicle adoption rates
that may not be feasible given vehicle costs, charging constraints, and range limitations.
Bainbridge Island has high rates of electric vehicle adoption compared to Kitsap County17, which provides
a strong foundation for rapid EV adoption, a key component of projected reductions in transportation
emissions for the city. However, other CAP goals, such as a 25% reduction in VMT per capita by 2030 and
a 50% reduction by 2045, cannot be addressed by electrifying passenger vehicles. Recognizing the
additional benefits from VMT reduction beyond GHG emissions (improved safety, expanded options, etc.),
Fehr & Peers analyzed the recently adopted Sustainable Transportation Plan to understand the VMT and
GHG reduction potential and to identify additional strategies to achieve the CAP goals. A description of
the methodology and results of the analysis is described in the next section.
16 Based on actions identified in the Airport Transport Action Group 2050 Plan. 17 Approximately 3% of passenger vehicles on Bainbridge Island were electric in 2021, compared to less than 1% all vehicles in Kitsap County
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Sustainable Transportation Plan
Building on actions outlined in the CAP, the City developed a Sustainable Transportation Plan (STP) in
2022, which identifies transportation projects that support the City’s GHG emission reduction goals,
improve transportation safety, and expand mobility options for people traveling on Bainbridge Island. The
projects in the adopted STP18 were classified into three categories: walking/rolling/biking projects, transit
and mobility projects, and non-infrastructure (programmatic) support. Fehr & Peers evaluated the
potential VMT reduction from the STP projects and identified additional strategies that could further
support the City’s climate action goals.
Evaluation of Infrastructure Improvements
Fehr & Peers used mode share data to determine the VMT and GHG emissions reduction potential of
walking, rolling, and biking projects in the STP. Table 14 shows the existing mode share in Bainbridge
Island, which is heavily skewed towards private vehicle trips. Because of the island’s geographic size and
development patterns, most vehicle trips are between two to six miles. These shorter vehicle trips are well
suited to be replaced by walking or biking trips, provided the City continues to build out a more
comprehensive multimodal network.
Table 14: Existing Citywide Mode Share
Mode Existing Mode Share1
Drive 84%
Transit2 7%
Walk 8%
Bike 1%
Total 100%
1. PSRC Household Travel Survey 2017-2019, includes all trips that start or end on Bainbridge Island 2. Includes bus, vanpool, and ferry trips
Fehr & Peers used Geographic Information Systems (GIS) files provided by the City to map and determine
the length of new bikeways, sidewalks, and roadways with traffic calming projects that would be added to
Bainbridge’s multimodal network after construction of the STP Connecting Centers, shown in Table 15.
Table 15: Existing and Future Multimodal Networks
Network Existing Miles STP Project Miles Future Miles
Bicycle Network 23 23 46
Pedestrian Network 50 14 64
Traffic Calmed Roads 23 13 36
Source: Fehr & Peers, 2023
18 Scenario 2: Connecting Centers
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The STP projects will more than double the city’s existing bikeway network and increase the sidewalk
network by almost 30%. The traffic calming projects focus on improvements near schools and parks, and
many of these projects provide shoulder enhancements to improve comfort for people biking.
The pedestrian and bicycle projects are located on arterial and collector streets and connect important
points of interest across the Island, including schools, neighborhood centers, shopping, and parks. Using
mode share data from other cities that were similar in terms of weather, topography, and infrastructure,
construction of the STP projects to build out a strategic multimodal network could result in a future active
mode share around 16% by 2035 (shown in the second column of Table 16).
Table 16: Future Potential Citywide Mode Share (2035)
Mode Existing Mode Share1 Potential Mode Share
Drive 84% 77%
Transit2 7% 7%
Walk 8% 11%
Bike 1% 5%
Total 100% 100%
1. PSRC Household Travel Survey 2017-2019, includes all trips that start or end on Bainbridge Island 2. Includes bus, vanpool, and ferry trips Source: Fehr & Peers, 2023
This change in mode share could realize up to 600,000 new annual walk trips and 1,000,000 new annual
bike trips citywide. To estimate the associated VMT reduction, the change in walk trips was multiplied by
an average walk distance of 1 mile, and the change in bike trips multiplied by an average bike distance of
2.5 miles. The reduction in VMT from new walk and bike trips was then divided by the total internal-
internal VMT, for a total VMT reduction of about 5% from bike improvements, and 1% for pedestrian
improvements.
Safe Routes to School
Safe Routes to School programs aim to reduce school related vehicle trips by making it easier for students
and their families to walk or bike to school. To determine the VMT and GHG emissions reduction potential
of implementing a Safe Routes to School program, Fehr & Peers drew on research compiled by the
California Air Pollution Control Officers Association (CAPCOA).19 It was determined that Safe Routes to
School programming would reduce school-related VMT by 4% since Safe Routes to School programs are
similar to Commute Trip Reduction Marketing (CAPCOA Measure T-5).20
The 4% potential VMT reduction from Safe Routes to School programming was applied to the share of
school-related vehicle trips on Bainbridge Island to determine the potential trip reduction from Safe
Routes to School programs. About 5% of vehicle trips on Bainbridge Island are directly related to school
19 Transit, mobility projects, and programmatic elements are not quantified because they are not currently funded. These programmatic elements are included in the Strategy VMT evaluation in the section that follows. 20 Defined by CAPCOA as programs to discourage single-occupancy vehicle trips and encourage alternative modes of transportation such as carpooling, taking transit, walking, and biking, thereby reducing VMT and GHG emissions.
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transportation; consequently, Safe Routes to School programming has the potential to reduce total
vehicle VMT in Bainbridge Island by 0.2%.
Total VMT Reduction
As shown in Table 17, implementing strategies from the adopted STP scenario could reduce total and per
capita on-island VMT by about 6%, a value below the CAP target of 25% reduction in per capita VMT by
2030. If the City continues to expand the multimodal network and implement supporting strategies to get
people traveling out of their personal car, this VMT reduction would continue to increase over time.
Table 17: VMT Reduction from STP Strategies
STP Strategy VMT Reduction
Bike Network Improvements & Traffic Calming -5.1%
Pedestrian Network Improvements -0.8%
Safe Routes to School -0.2%
Total -6.1%
Source: Fehr & Peers, 2023
This estimated VMT reduction is dependent on construction of the “all ages and abilities”, or low stress,
multimodal network identified in the adopted STP scenario. As shown in Figure 12, for a bicycling
network to truly support users of all ages and abilities, its most fundamental attribute should be low stress
connectivity, that is, providing routes between people’s origins and destinations that do not require
cyclists to use roadways with undue traffic stress, such as high vehicle volumes or speeds. Building out this
infrastructure is vital to supporting the mode share shift and associated VMT reductions from the
additional strategies analyzed below.
Figure 12: Designing Bicycle Facilities for All Ages and Abilities21
21 ‘Designing for All Ages & Abilities’, https://nacto.org/wp-content/uploads/2017/12/NACTO_Designing-for-All-Ages-Abilities.pdf
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VMT and GHG Emissions Reduction
Strategies
Introduction
By 2045, it is expected that on-road GHG emissions on Bainbridge Island will decrease about 85%
compared to the 2014 baseline, largely as a result of passenger vehicle and freight electrification.
However, that assumes aggressive vehicle electrification targets are met over a long period of time (i.e.,
65% of new vehicle sales are electric by 2030). Actions taken now to reduce VMT can help achieve the
shorter-term CAP goal to reduce emissions 60% by 2035 and provide a strong foundation for long-term
GHG emissions reduction (90% reduction by 2045).
Implementation of the STP projects will provide Bainbridge Island with a strong multimodal network, but
additional strategies are required to get motorists out of their personal vehicles, and substantially reduce
VMT and GHG emissions on the island. This analysis presents strategies that build on the STP to reduce
GHG emissions below the levels estimated under the Projected scenario.
Reducing VMT will require strategies that shift travel away from single occupancy vehicles. These
strategies are expected to have co-benefits that extend beyond reducing emissions, including:
• improving public health by reducing toxic air contaminants and increasing physical activity,
• reducing fuel use and costs,
• reducing on-road pollution and improving ecosystem health through better water and soil quality,
• reducing congestion and improving comfort for all road users,
• reducing wear and tear on City roadways and associated maintenance requirements and costs, and
• improving safety for vulnerable road users like pedestrians and cyclists.
With limited resources to commit to address climate change, the purpose of this analysis is to assess
which strategies will have the most emission reduction benefit. The most desirable strategies to reduce
GHG emissions are those that are cost effective, offer a large potential to reduce emissions, are achievable
in the near-term and can be independently implemented by the City.
VMT Reduction Strategies
Bainbridge Island has distinct travel patterns that are well suited to travel by non-auto modes. The Travel
Markets analysis using StreetLight Data showed that over 60% of resident vehicle trips are under five
miles in length; these short trips are well suited towards alternate modes, particularly biking as e-bikes
have become more commonplace. Similarly, while land use patterns on Bainbridge Island are well
established and predominantly residential, there are opportunities to situate future residential and
34
commercial development within or near existing transit and activity centers, which can reduce the need
for vehicle travel.
Fehr & Peers quantified the potential reduction in VMT and GHG emissions from eight strategies that
ranged from land use changes, such as additional workforce housing, to incentive programs, such as
subsidies for electric bicycles. The evaluated strategies were selected based on their suitability and
feasibility for implementation on Bainbridge Island. Some strategies, such as parking pricing, e-bike
subsidies, and electric car-share, can be directly implemented by the City, while strategies such as
expanded transit service and the bike and pedestrian projects from STP are already planned and partially
or fully funded. Other strategies, such as developing workforce housing, were selected because they are
well suited to mitigate employee trips from off-island, which contribute substantially to the city’s VMT.
Finally, the analysis also considers strategies that have started to emerge as a result of social and
technological change, including increased telework and ecommerce, which may decrease the frequency of
off-island work trips and shopping trips.
In alignment with the City’s CAP goals, the analysis assumes that strategies will be implemented over a
25-year period, between 2021 and 2045 as shown in Table 18. Some strategies, such as workforce
housing, are expected to take many years to implement as they will require coordination across many
public and private stakeholders. Other strategies have established implementation timelines. For example,
STP projects are expected to be rapidly constructed over the next ten to twelve years and could be
complete by 2035.
Table 18: Assumed Phasing of Strategies over Time
Strategy Start Year Description
STP Projects 2025
The STP projects refer to the capital improvements detailed in the
“Connecting Centers” scenario of Bainbridge Island’s Sustainable
Transportation Plan. The analysis assumes 25% of project miles are
built by 2025, 75% by 2030, 100% by 2035.
Enhanced Transit 2025
The 2022 – 2024 Long Range Transit Plan (LRTP) for Kitsap Transit
plans for three new transit lines to serve Bainbridge Island including
a Bainbridge Intra-Island line, a circulator in Downton Winslow, and a
new Bainbridge-Poulsbo-Viking line. The LRTP also plans to expand
existing on-demand service on Bainbridge Island. The analysis
assumes one new route is in service by 2025, and the remaining
routes are in service by 2030.
Land Use – Workforce
Housing 2030
The City of Bainbridge Island plans to accommodate more than 400
units of muti-family housing in Winslow by 2036. This strategy
assumes that 50% of units would be dedicated to affordable and/or
workforce housing. The analysis assumes that 50% of housing could
be built by 2030.
35
Strategy Start Year Description
Land Use – Retail Trips 2025
This strategy focuses on reducing the number of off-island retail trips
by developing infrastructure to support deliveries and provide an
alternative to off-island retail trips. It is assumed 10% of retail trips
shift to ecommerce by 2025 and increase linearly thereafter based on
post-pandemic trends.
Telework 2021 This strategy assumes that the increase in remote work noted during
the COVID-19 pandemic is maintained throughout all horizon years.
Parking Pricing 2030 This strategy prices parking in downtown Winslow at $2/hour
beginning in 2030 and increases with inflation thereafter.
Car Share 2025 Under this strategy, five electric car share vehicles would be deployed
by 2025, 10 by 2030, and 20 by 2035.
E-Bike Subsidies 2025
This strategy would provide $3M to an e-bike rebate program
between 2025 and 2045. A $1,000 subsidy would be made available
to 200 households in 2025, 400 households in 2030, and 800
households in 2035, 2040, and 2045.
Key Takeaways
Some strategies show high potential to reduce VMT and GHG emissions and, if expanded in scale, could
move the city closer towards meeting the CAP goals. The expected contribution of each strategy to
reducing VMT is described under ‘Impact of VMT Reduction Strategies.’
Building on Kitsap Transit’s Long-Range Plan that envisions new fixed route and expanded on-demand
transit service, Bainbridge Island’s STP recommends implementing additional transit and mobility
programs that will support mode shift and reduce VMT. Some strategies include developing mobility hubs
at key locations across the island (including the ferry terminal and other neighborhood centers) to
connect multi-modal transportation options and support the use of non-auto modes. The STP also
contains programmatic elements, including education and outreach, that are not expected to directly
reduce VMT on their own, but are fundamental to the success of planned investments in multi-modal
infrastructure and transit service in supporting VMT reduction. Therefore, the City should prioritize
securing funds for implementation of the STP’s programmatic elements and continue coordination with
Kitsap Transit on execution of the Long-Range Plan.
Beyond telework, the analysis shows e-bike subsidies can play a key role in reducing VMT on an ongoing
basis. Current, successful e-bike subsidy programs, such as the City of Denver’s program, provide a
subsidy between $400 - $1,200 depending on household income and type of e-bike.22 The City should
prioritize securing funding for an initial e-bike subsidy pilot program structured similar to the City of
22 City of Denver, E-Bike and E-Cargo Bike Instant Rebates, https://denvergov.org/Government/Agencies-Departments-Offices/Agencies-Departments-Offices-Directory/Climate-Action-Sustainability-Resiliency/Sustainable-Transportation/Electric-Bikes-E-Bikes-Rebates
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Denver’s program. If the pilot program were to be expanded, and more households had access to the
subsidy, the city could see additional VMT reductions, especially when implemented with supportive
strategies, such as the bicycle infrastructure projects from the STP that make it more attractive to bike
around Bainbridge Island.
Employee trips are another source of on-island VMT that can be addressed through several of the VMT
reduction strategies. Remote work became widespread during Covid-19; in 2021, remote work reduced
employee VMT by 22% as compared to 2019 and reduced all VMT 9% below the 2014 baseline. While the
precise future characteristics of remote work are uncertain, it is unlikely that employee trips will return to
pre-2020 levels. Employee trips can be further reduced through strategies like workforce housing
development that enable more people to live and work on Bainbridge Island. This analysis assumes that a
portion of expected multifamily housing growth could be dedicated to workforce housing by 2030,
reducing VMT by 1%. Additional workforce or affordable housing development have the potential to
substantially further reduce VMT.
Since retail on Bainbridge Island is limited, many residents travel off-island to shop. Shifting existing
retail trips to e-commerce can reduce VMT by reducing off-island personal vehicle trips without
reducing access to daily essentials and other goods. Home shopping and deliveries have increased
steadily over the past ten years and experienced a significant increase during the COVID-19 pandemic.
The City can support these recent trends by developing adequate delivery infrastructure, such as
consolidated delivery locations and loading zones.
Although not considered within this study, policy changes to facilitate the development of commercial
and retail establishments on Bainbridge Island have a high potential to reduce VMT. Currently,
restrictions in the City’s building code limit the construction of select commercial and retail
establishments. In 2022, developers withdrew a project that would have created two new buildings with
businesses, market rate housing, and affordable housing in Downtown Winslow because of density
restrictions and parking requirements mandated by the City’s Comprehensive Plan.23 Since development
has historically proved challenging, residents must drive to Poulsbo/Silverdale to access additional retail
and services, which is a large contributor to the city’s VMT.
Implementing parking pricing is expected to have a small impact on VMT, since proposed charges are
expected to be low relative to the overall cost of driving, reflecting the contentious and political nature of
pricing parking and VMT. On the other hand, adopting a pricing structure for VMT that reflects the actual
cost of vehicle use could substantially reduce VMT beyond what Fehr & Peers has modeled.
Telework is expected to play a large role in reducing VMT and associated GHG emissions. However, there
are minimal actions that can be taken at the municipal level to encourage teleworking, and it is unlikely
that the prevalence of telework will expand beyond levels observed at the height of the Covid-19
pandemic between 2020 and 2021.
23 Bainbridge Review, Gateway to Winslow project withdrawn, https://www.bainbridgereview.com/business/gateway-to-winslow-project-withdrawn/
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Cost Comparison
The VMT reduction strategies also vary in cost, both on an absolute basis and when normalized to the
amount of VMT reduced. Table 19 shows the cost of reducing VMT on a cost per VMT basis for three
strategies which are directly implementable by the City. E-bikes have the lowest cost per VMT eliminated,
however the effectiveness of e-bikes as a tool to reduce VMT is dependent on the sufficient provision of
bike infrastructure as envisioned in the STP. Cost per VMT eliminated decreases over time for the STP
strategies and car share because both involve up-front capital expenditures. Cost per VMT eliminated
decreases over time for e-bike subsidies because it is assumed that households will continue to replace
vehicle trips with e-bikes in subsequent years.
Table 19: Cost per VMT Eliminated
Strategy 2025 2030 2035 2040 2045 Average
STP Strategies $3,200 $2,000 $700 $0 $0 $700
Car Share* $1,400 $700 $700 $400 $400 $600
E-Bike Subsidies $400 $150 $100 $100 $50 $100
Source: Fehr & Peers, 2023 *For carshare, this is the Cost/VMT shifted to zero-emission sources.
Impact of VMT Reduction Strategies
Table 20 shows the potential VMT reduction associated with each strategy, and the total percent
reduction for each horizon year compared to the Projected scenario.
Table 20: Daily VMT Reduction from Strategies
Strategy 2025 2030 2035 2040 2045
STP Strategies -960 -3,050 -4,280 -4,510 -4,760
Enhanced Transit -480 -2,210 -2,350 -2,500 -2,650
Land Use – Workforce Housing 0 -2,040 -2,140 -2,260 -2,380
Land Use – Retail Trips -1,060 -2,250 -2,960 -3,740 -4,210
TDM (Telework) -21,580 -22,810 -24,040 -25,330 -26,700
Parking Pricing 0 -2,900 -2,920 -2,920 -2,910
Car Share* 0 0 0 0 0
E-Bike Subsidies -510 -3,080 -7,180 -11,280 -15,390
Total Reduction -24,590 -38,340 -45,870 -52,540 -60,000
Projected Future VMT 279,160 284,140 298,250 312,790 327,300
Percent VMT Reduction -9% -14% -15% -17% -18%
Source: Fehr & Peers, 2023 *Limited evidence to support that VMT is reduced through car share, therefore while electric car share can reduce GHG emissions, it is less evident that
electric car share can reduce VMT.
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The selected strategies are expected to reduce total VMT by 14% by 2030 and 18% by 2045, as shown in
Table 20 and Figure 13. While total VMT continues to increase as population and jobs grow on
Bainbridge Island, VMT per capita could be reduced about 6% by 2030 and 12% by 2045 compared to the
2014 baseline.
Figure 13: Estimated Daily VMT Reduction
The CAP goal related to VMT is to reduce VMT per capita by 50% in 2045, compared to the 2014 baseline.
Based on this analysis, the city is not on track to meet this goal. However, it is important to understand
this goal in relation to the rest of the region. PSRC recently completed their modeling work for VISION
2050 and estimated a 20% reduction in VMT per capita across the 4-county region by 2050. While PSRC
has not yet released VMT per capita targets for communities within their jurisdiction, Fehr & Peers
anticipates that Bainbridge Island’s goal of a 50% VMT per capita reduction is more ambitious than what
is projected by PSRC.
GHG Emissions Reduction
Fehr & Peers combined the estimated VMT reduction rates from the strategy analysis with average
emissions factors for each horizon year to project the GHG emissions. Given the uncertainty around EV
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adoption rates, Fehr & Peers analyzed the GHG emissions reduction potential of all strategies under two
EV adoption scenarios:
• PSREA (faster EV adoption): used EV adoption assumptions from the Projected scenario from the
wedge analysis, which assumes 65% of new vehicle sales are EV by 2030, and 100% by 2035.
• Slower EV adoption: used a more conversative EV adoption rate than the Projected scenario, with
50% of new vehicles sales EV by 2030, and 100% by 2040.
Figure 14 shows the expected GHG emissions reduction from the selected strategies under both
scenarios.
Figure 14: Estimated GHG Emissions Reduction
Table 21 summarizes the estimated GHG emissions reduction associated with both EV adoption
scenarios, highlighting how each individual strategy contributes to the total GHG emissions reduction
over time. With the slower EV adoption scenario, strategies to reduce VMT have a greater emissions
benefit in the long-term because the share of internal combustion engine (ICE) vehicles is higher under
this scenario and results in VMT that is more carbon intensive. However, as shown in Figure 14, the faster
EV adoption scenario results in lower overall emissions because there are fewer ICE passenger vehicles on
the road and the absolute quantity of GHG emissions eliminated due to the VMT reduction strategies
decreases as horizon years extend further into the future.
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Table 21: Annual GHG Emissions Reduction (Share of Reduction by Strategy)
Strategy 2025 2030 2035 2040 2045
STP Strategies 4% 8% 9% 8% 8%
Enhanced Transit 2% 6% 5% 5% 4%
Land Use – Workforce Housing 0% 5% 5% 4% 4%
Land Use – Retail Trips 4% 6% 6% 7% 7%
TDM (Telework) 87% 59% 52% 48% 45%
Parking Pricing 0% 8% 6% 5% 5%
Car Share* 1% 1% 2% 1% 2%
E-Bike Subsidies 2% 8% 15% 21% 26%
Estimated MTCO2e Reduction from the Strategies (assuming faster EV adoption) -2,280 -2,540 -2,090 -1,280 -600
Estimated MTCO2e Reduction from the Strategies (assuming slower EV adoption) -2,280 -2,700 -2,450 -2,010 -1,400
Source: Fehr & Peers, 2023
Recommendations
The selected VMT reduction strategies could reduce on-road GHG emissions by 600 to 1,400 MTCO2e
annually in 2045, which falls short of the CAP goal to reduce GHG emissions by 18,000 MTCO2e through
VMT reduction. However, this gap is largely offset by GHG reductions from a faster rate of vehicle
electrification compared to what was anticipated when the CAP was developed. The updated analysis
from this study shows electrification could reduce transportation emissions by about 25,000 MTCO2e by
2045 as shown in Table 22.
Table 22: Estimated Emissions Reduction as Compared to Climate Action Plan Goals
Action Reduction in GHG emissions by 2045 from 2014 Baseline
(MTCO2e)
Climate Action Plan Goal Estimated Reduction
VMT reduction (all strategies) -18,000 -600 MTCO2 to -1,400 MTCO2
On- & off-road vehicle electrification -18,000 -25,000 ✓
Ferry electrification -14,000 -13,400 ✓
Air travel reduction and improved fuel
efficiency -10,000 -6,000
Total -60,000 -40,000
Source: Fehr & Peers, 2023
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As demonstrated above, to substantially reduce near- and long-term on-road GHG emissions, the City
needs to pursue additional VMT reduction strategies that build on the STP projects while supporting a
citywide transition to electric vehicles.
Consequently, the City should continue to move forward on implementing strategies that have been
planned and funded through the city’s impact fee programs, focusing first on construction of the capital
improvements from the STP. For unfunded strategies, such as e-bike subsidies, the City should begin to
identify funding sources for the program. The Washington 2023-2025 State budget has $2M for
employers, governments, tribes, or non-profits to establish e-bike lending libraries; while funds could not
be used for an e-bike rebate program, an e-bike lending library could support a future e-bike program by
building interest in e-bikes among Bainbridge Island residents.24
Bainbridge Island could also explore expanding the scale of proposed strategies to further reduce VMT
and GHG emissions. Specifically, the City could take the following actions:
• Consider securing additional funding to support a larger e-bike subsidy program than what was analyzed so more households can benefit from the program.
• Consider implementing regulatory changes or incentives to expedite the development of additional multifamily housing.
• Consider pricing parking in Downtown Winslow at a rate that is commensurate with the actual
cost of driving to encourage travel to Downtown Winslow by alternate modes.
In addition, the City could consider land use policy changes that have the potential to alter travel patterns
to further reduce VMT and emissions. Specifically, the City could take steps to reduce off-island vehicle
travel by encouraging the development of mixed-use retail and commercial land uses in Downtown
Winslow. This has a high potential to reduce VMT since the travel market analysis shows that many off-
island vehicle trips are for shopping or errands. While off-island trips are a smaller proportion of total
trips, the average trip length is longer and therefore these trips contribute disproportionately to VMT.
Finally, the analysis shows that the electrification of passenger and freight vehicles will play a central role
in reducing emissions from transportation sources on Bainbridge Island. The City should begin to consider
the level of public investment that will be required to develop an electric vehicle charging network
including the number of chargers needed, the type of chargers needed, and where chargers should be
located to ensure equitable access for people who may not have access to charging at home.
Implementation
The City has started to take action to implement emissions reduction strategies, and additional actions
that could be taken are presented in Table 23. Newer strategies, such as e-bike subsidies, actions may
include planning and policy development, while other strategies, such as the STP strategies, could be
ready for design and construction. While many strategies can be spearheaded by the City, local and
24Washington State Legislature, HB 1125, https://lawfilesext.leg.wa.gov/biennium/2023-24/Pdf/Amendments/House/1125-S.E%20AMC%20CONF%20S3376.1.pdf
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regional coordination is vital to successful implementation, especially among key stakeholders including
Bainbridge Island residents, local community groups and businesses, and Kitsap Transit.
Table 23: Recommended Implementation Actions for VMT Reduction Strategies
Strategy Action Source (If Applicable)
All
Secure funding sources for implementation actions, including reauthorizing Transportation Benefit District Fees and adopting the City’s updated Transportation Impact Fee Program.
City of Bainbridge Island, Sustainable Transportation Plan, 2022
STP Strategies
Implement policies to support multimodal travel including a Safe Routes to School program, continuing to monitor speed limits across the island, and a gravel shoulder maintenance program.
City of Bainbridge Island, Sustainable Transportation Plan, 2022
Move forward with implementation by establishing oversight groups to guide prioritization, sequencing, and spending levels, as described in the Sustainable Transportation Plan.
City of Bainbridge Island, Sustainable Transportation Plan, 2022
In coordination with implementing a mobility hub at the ferry terminal, launch an outreach campaign targeted at visitors on how they can visit Bainbridge Island without their personal vehicle.
Enhanced Transit
In consultation with Kitsap Transit, develop a robust marketing, outreach, and educational program to inform Island residents and those who traverse the Island from outside about public transit options, including park and rides and BI ride.
City of Bainbridge Island, Sustainable Transportation Plan, 2022
Land Use – Workforce Housing
Continue to advance recommendations in the City of Bremerton & Kitsap County Affordable Housing Recommendations Report aimed at developing more affordable and workforce housing.
Kitsap County Affordable Housing Recommendations Report
Land Use – Retail Trips
Require land use planning that explicitly incorporates walking and bicycling networks, promotes greater density, and optimizes space to minimize the distance people have to travel by car.
City of Bainbridge Island, Sustainable Transportation Plan, 2022
TDM (Telework)
Continue to monitor levels of remote work to understand how remote work is influencing VMT.
Develop policies to facilitate remote work for Bainbridge Island residents, such as providing incentives for flexible use spaces that can be used for coworking space.
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Strategy Action Source (If Applicable)
Develop guidelines for remote work for City employees to maintain levels of remote work observed following the Covid-19 pandemic.
Parking Pricing
Evaluate increasing the price of parking at the ferry to encourage people to take public transportation, bike or walk.
City of Bainbridge Island, Climate Action Plan, 2020
Reevaluate data from the 2018 Downtown Parking Strategy and revisit the recommendation to keep parking unpriced in Downtown areas.
Car Share
Evaluate options to expand the current electric carsharing pilot program (ZEV Co-op25), including direct municipal ownership and operation as well as partnership opportunities.
E-Bike Subsidies
Explore funding opportunities at the Federal, State, Regional, and Local levels for e-bike subsidies.
Evaluate opportunities to establish a municipal e-bike lending library leveraging funding made available in the 2023-2025 WA State budget.
EV Readiness
Increase electric charging infrastructure through public private partnerships and pursue state grant funds for electric vehicle infrastructure along major highways.
Community Based Strategies to Reduce GHG Emissions, Western Washington University, June 2019
Partner with utility companies to provide rebate programs for electric vehicle supply equipment.
Pass an ordinance requiring new multi-family residential developments to require EV ready infrastructure.
25 https://zev.coop/