Sound Transit Express

Sound Transit Express

A double-decker Sound Transit Express bus on Route 513 at Mountlake Terrace Freeway Station
Parent	Sound Transit
Founded	1996
Headquarters	Seattle, Washington
Locale	Puget Sound region
Service area	King, Pierce, and Snohomish
Service type	Public Transit
Routes	23
Hubs	8
Fleet	312 buses
Daily ridership	30,000 (weekdays, Q1 2025)[1]
Annual ridership	9,325,400 (2024)[2]
Fuel type	CNG, Diesel, and Diesel-electric hybrid
Operator	Community Transit, King County Metro, and Pierce Transit
Website	www.soundtransit.org

Sound Transit Express (ST Express) is a network of regional express buses, operated by the multi-county transit agency, Sound Transit. The routes connect major regional hubs throughout 53 cities in three counties (King, Pierce, and Snohomish) in the Puget Sound region. Sound Transit Express ranks first in the nation in the number of commuter bus passengers carried and in vehicle miles driven.^[3] The first nine routes and 114 buses began carrying passengers on September 19, 1999.^[4][5] In 2024, the system had a ridership of 9,325,400, or about 30,000 per weekday as of the first quarter of 2025.

Unlike a typical transit bus, Sound Transit Express routes typically make limited stops as they travel longer distances on the freeways. Most routes operate seven days a week, with runs throughout the day. Where available, buses use transit-only lanes, high-occupancy vehicle lanes, high-occupancy toll lanes, express lanes, bus bypass shoulders,^[6] and direct access ramps to speed travel times.

While Sound Transit oversees, plans, and funds the service, operation and maintenance of the buses is contracted out to Community Transit (who subcontracts with Transdev), King County Metro and Pierce Transit.^[7]