SEPA checklist guidance, Section B: Transportation

We provide guidance to help applicants complete the Transportation section of the SEPA Section B: Environmental elements checklist.

14. Transportation

a. Identify public streets and highways serving the site or affected geographic area, and describe proposed access to the existing street system. Show on site plans, if any:

Review agencies need information to determine if a proposal will contribute to existing safety, noise, dust, maintenance, or other transportation problems. This includes increasing road use. Describe site access roads and provide a public street or vicinity map showing access to the site. Highways or other listed major arterials don’t need to directly access the site, but these roads are likely to be used by employees, customers, or residents, as well as transport materials or goods on and off the project.

"Traffic hazards" also is an element of the environment under SEPA. It is necessary to evaluate the existing environment and the proposed project in terms of transportation safety. There could be a need to include data such as the following:

  • What is the crash history on streets affected by the project?
  • Will changes in the street or traffic operations affect the crash history?
  • Are there new risks being introduced that could be mitigated? (Consider operating characteristics of general-purpose vehicles, trucks, transit riders, pedestrians, and bicyclists.)

Additional resources:

b. Is the site or affected geographic area currently served by public transit? If so, give a general description. If not, what is the approximate distance to the nearest transit stop?

Include details about types of public transportation, as well as proximity to nearest train stations and/or bus stops.

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c. Will the proposal require any new — or improvements to existing — roads or streets, or pedestrian, bicycle, or state transportation facilities, not including driveways? If so, give a general description and indicate whether it’s public or private.

Describe and provide a map of confirmed and probable new roadways, including the following:

  • Number of lanes and turn lanes
  • Road surfacing
  • Lighting and signage
  • Stormwater conveyance
  • Safety barriers

Additional resources

d. Will the project or proposal use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, give a general description.

Describe the adequacy of available facilities and services. Include information about how the proposal will use air, water, and/or rail transportation. Provide information about:

  • Transportation of raw materials
  • Product delivery
  • Waste disposal
  • Employee or residential commutes

e. How many vehicular trips per day would the completed project or proposal generate? If known, indicate when peak volumes would occur and what percentage of the volume would be trucks (such as commercial and non-passenger vehicles). What data or transportation models were used to make these estimates?

Measure the number of vehicle trips directly associated with the proposal, as well as indirect results of structural or facility uses. Identify the number of trips to and from the project site during a given 24-hour period. In addition, identifying information about peak-hour trips can speed the review of a project.

  • Direct effects: Occur at the same time and location as the proposal occurs.
  • Indirect effects: Occur later, but are still reasonably foreseeable. Indirect effects can include those related to changes in land use, population density or growth rate, and related environmental impacts.

Describe the availability of public transportation, car or van pooling, flexible work schedules, telecommuting, and other measures to decrease traffic generated by the project. Other issues include: 

  • Is the study area large enough to include all indirect impacts?
  • Does the study area include critical intersections?
  • Are traffic counts recent?
  • Were counts taken during critical time periods?
  • Have assumptions used in the technical analysis been clearly identified?
  • Do calculated levels of service seem reasonable?
  • Does the community have acceptable service standards?
  • Does the proposed site agree with the submitted site plan?
  • Have trip rates been adjusted to account for public transportation, pedestrians, or pass-by trips?
  • Does the directional distribution of the site traffic seem reasonable?
  • Has pedestrian circulation been accommodated?
  • Is parking adequate to meet demand?

f. Will the proposal interfere with, affect, or be affected by the movement of agricultural and forest products on roads or streets in the area? If so, give a general description.

Congestion occurs when the number of vehicles seeking to use a mode or a choke point at any time exceeds capacity. Studies show transporting 1 ton of freight uses 1 gallon of fuel to move 202 miles by rail; 514 miles by inland barge; and 59 miles by truck.

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g. Proposed measures to reduce or control transportation impacts, if any: Identify public streets and highways serving the site and describe proposed access to the existing street system.

Mitigation includes avoiding, reducing, or countering environmental impacts, including:

  • Providing additional parking
  • Road improvements such as widening or adding signs, signals, and turn lanes
  • A transportation plan to reduce commute trips per day, particularly during peak hours
  • In-lieu fees
  • Consolidating trips by providing mixed-use development
  • Alternative modes of transportation
  • Pedestrian-friendly design, including smaller setbacks, parking behind buildings, and building sidewalks

Additional resources