Part-time transit lanes

Overview

The Part-Time Transit Lanes (PTTL) project is one of the six ground-breaking projects that make up Contra Costa Transportation Authority’s (CCTA) INNOVATE 680 program. This program seeks to implement a carefully curated suite of projects that, when operating together, will address corridorwide congestion, travel delays, and long-standing operational challenges along Interstate 680 (I-680) in Contra Costa County.

The PTTL project will enable buses to travel on the right shoulder (or transit-only lanes) to bypass congestion during periods of heavy traffic. This will not only help reduce congestion on the freeway, but it will also make transit more reliable. In Contra Costa County, part-time transit lanes are currently planned between Bollinger Canyon Road and the Walnut Creek BART station.

Several U.S. cities have successfully implemented part-time transit lane systems, some of which have been in operation for a number of years.

Minneapolis-St. Paul, MN
Atlanta, GA
Chicago, IL
Columbus, OH
Miami, FL
Raleigh-Durham-Chapel Hill, NC

How Part-Time Transit Lanes Work

Lane speed limit = 35 mph

Bus travel speed cannot be greater than 15 mph over the bypassing traffic speed.

For example, if traffic is stopped (zero miles per hour), the bus using the part-time transit lane can travel at a max speed of 15 mph.
0mph + 15mph = 15mph max speed

If congested traffic is moving at 20 miles per hour, the bus using the part-time transit lane can travel at the max speed of 35 mph.
20mph + 15mph = 35mph max speed

Buses will yield to all traffic incidents on shoulder