Preview our new website

Lifecycle of a typical project

Lifecycle of typical transit project.

Ever wonder why it takes so long to build a transit project? The reason is that major projects often take years of public involvement, planning, engineering and analysis. This covers Sound Transit work on a typical light rail project.


The goal of this phase is to answer two basic questions:

  • What areas will it serve?
  • What type of transportation technology best suits the need?

During this phase community members and organizations, commuters and other stakeholders help shape the project. Public meetings provide updates and help us gather feedback. Jurisdictions, like cities and counties, partner with us to gather data.

This is also the phase when voters may be asked to fund the project. 

Alternatives development

Alternatives development: takes about one year

During this phase:

  • Alternatives are identified, evaluated and narrowed. Routes and technologies, such as bus, elevated rail, subway, etc., are evaluated.
  • We meet with communities, stakeholders, elected officials and the public to hear comments on the alternatives.
  • The Sound Transit Board typically identifies the alternative(s) to be studied during the next phase, which is environmental review.

Environmental review & preliminary design

Environmental review and preliminary design: takes 1 - 4 years

This phase identifies potential environmental impacts of the alternatives, allows for public comment and provides information for the Board to consider in selecting the project to be built. The project's design moves from conceptual to preliminary.

The level of review and documentation depends on the scope of the project and its potential for environmental impacts.

  • An Environmental Impact Statement (EIS) is prepared for large projects with potentially significant impacts.
  • An environmental assessment, State Environmental Protection Act (SEPA) checklist or other document may be prepared for projects not requiring an EIS. 

During this phase:

  • Field work may include observing and counting traffic, studying natural resources and land use and monitoring noise.
  • If required, a Draft EIS is published followed by a public comment period. Responses to those comments are found in the Final EIS.
  • Preliminary design is completed.
  • The Sound Transit Board selects the project that will eventually be built.
  • For federalized projects requiring an EIS, the lead federal agency issues an environmental decision document, called a Record of Decision (ROD).

Final design

Final design: takes 2 - 3 years

In this phase, architects and engineers define what the stations will look like as well as the technical specifications for the stations and tracks.

During this phase:

  • Field work includes testing soil conditions and ground water levels, surveying, and locating utilities.
  • Large projects are divided into several smaller contracts to encourage competition.
  • Projects are typically broken into design milestones: 30 percent, 60 percent and 90 percent. At each milestone, the agency asks for public input on the station design.
  • Artists for permanent station art are selected through a public process. The need for temporary art at construction sites is identified.
  • The agency acquires any necessary private property and easements.
  • Permits, including land use approvals, noise variances, storm water discharge and wetland impacts are acquired.


Construction: takes 5-plus years 

Sound Transit and its contractors balance the need to complete the project on time and on budget while minimizing construction impacts to the community. Construction time varies widely from project to project.

Some of the factors that can influence the schedule:

  • Large projects are technically challenging with numerous regulatory and other constraints.
  • External factors such as labor disputes, material shortages, unforeseen site conditions and weather can slow a project.
  • Especially complex or challenging projects, such as tunneling, can take seven years or more.

During this phase we're committed to maintaining open communications with the community and there are multiple opportunities and ways to stay informed.

Testing & pre-operations

Testing & pre-operations: Starts a year to six months before service begins

From the time construction wraps-up (and sometimes even before) to when service begins, work is underway to make sure that the project is ready and that the public is ready for it. The pre-revenue testing phase includes a safety certification process. Passengers can't begin riding until the service is certified.

Activities include:

  • Various simulations that make sure that communications, safety and emergency and other systems are running and working together.
  • Intersection signals, crossing gates and pedestrian signals are checked. Trains begin running without passengers to help pedestrians, bikers and drivers learn how to travel safely with trains.