Tri Delta Transit

Tri Delta Transit
Parent	Eastern Contra Costa Transit Authority
Founded	1977
Headquarters	801 Wilbur Ave, Antioch, California, United States
Locale	East Contra Costa County, California
Service type	bus service, paratransit
Routes	17 weekday, 6 weekend
Stops	approximately 650
Fleet	62 transit bus; 30 paratransit; 6 med vans; 8 microtransit Tri MyRide;
Daily ridership	4,700 (weekdays, Q2 2024)
Annual ridership	1,304,700 (2023)
Operator	Transdev
Website	trideltatransit.com

Tri Delta Transit, formally the Eastern Contra Costa Transit Authority, is a joint powers agency of the governments of Pittsburg, Antioch, Oakley, Brentwood, and Contra Costa County that provides bus service for the eastern area of Contra Costa County, California, United States.^[1] Tri Delta Transit local buses connect to the BART rapid transit system at Antioch, Pittsburg Center, Pittsburg/Bay Point and Concord. Tri Delta Transit buses also connect with County Connection bus service. In 2023, the system had a ridership of 1,304,700, or about 4,700 per weekday as of the second quarter of 2024.

Tri Delta Transit service began on June 6, 1977. Initial service was two local routes in Antioch and Pittsburg, which connected with express bus service serving BART. AC Transit operated the service under contract until 1984, when it was transferred to a private operator.^[4]

Overview of fixed-route service

Tri Delta Transit operates in eastern Contra Costa County and has stops in Antioch, Oakley, Brentwood, Bay Point, Pittsburg, Martinez, and Concord. Tri Delta Transit operates local and express routes on weekdays and local routes on weekends/holidays.

Major transfer points for the majority of Tri Delta Transit's routes include:

Brentwood Park & Ride in Brentwood
Oakley Park & Ride
Antioch BART station in Antioch
Pittsburg Center BART station in Pittsburg
Pittsburg/Bay Point BART station in Pittsburg
Los Medanos College in Pittsburg

Route list

Tri Delta Transit operates seventeen bus routes. On weekdays, all of them are operated throughout the cities of Concord, Bay Point, Pittsburg, Antioch, Oakley, Brentwood, and Martinez. On weekends, six of them are operated throughout the aforementioned cities except Concord and Martinez. They're intended to be the longer routes to cover the many segments of the weekday-only bus routes. Even though most of the routes have the same terminus, various of them have their own ways of reaching their terminus.^[5]

All weekday routes
Route	Westbound Terminal	Eastbound Terminal
200X	Martinez station (Amtrak)	Pittsburg/Bay Point BART
201X	Concord BART	Pittsburg/Bay Point BART
202X	Brentwood Park & Ride (loop back via Los Medanos College Brentwood Center)
300X	Antioch BART	Brentwood Park & Ride
379	Antioch BART	Antioch Medical Center
380	Pittsburg/Bay Point BART	Antioch BART
381	Pittsburg Marina	Los Medanos College
383	Wilbur and Cavallo Rd (Tri Delta Transit HQ)	Blue Goose Park
384	Antioch BART	Brentwood Park & Ride
385	Antioch BART	Brentwood Park & Ride
387	Pittsburg/Bay Point BART	Antioch BART
388	Pittsburg/Bay Point BART	Antioch Medical Center
389	Pittsburg/Bay Point BART (loop around via Bay Point)
390	Pittsburg/Bay Point BART	Antioch BART
391	Pittsburg Center BART	Brentwood Park & Ride
395	Antioch BART	The Streets of Brentwood
709	Pittsburg/Bay Point BART	Antioch BART
All weekend routes
380	Pittsburg/Bay Point BART	Antioch BART
381	Pittsburg Marina	Los Medanos College
388	Pittsburg/Bay Point BART	Antioch Medical Center
389	Pittsburg/Bay Point BART (loop around via Bay Point)
391	Pittsburg Center BART	Brentwood Park & Ride
395	Antioch BART	Streets of Brentwood