The part-time Transit Only Lane Demonstration Project allows for South Bay Rapid buses (Route 225), operated by specially trained drivers and equipped with innovative technology, to perform Bus on Shoulder (BOS) operations along I-805 and SR 94 during peak travel times.

Rapid Bus

During heavy traffic congestion, South Bay Rapid buses can operate on selected freeway shoulders between Downtown San Diego and National City, helping bus drivers to bypass slow traffic.  

The three-year pilot project includes the San Diego region’s first use of transit vehicle-to-infrastructure technology. Sensors embedded on these buses provide audio and visual alerts to the drivers regarding lane position and potential conflicts with other vehicles or obstructions along the corridor and shoulder.

Detailed performance monitoring will document on-time performance data, travel speeds, technology usage, enforcement issues, and rider/driver perceptions of the service. Participating agencies will use this data when planning future projects that include vehicle-to-infrastructure technology.

After the project’s three-year demonstration period, the freeway shoulders will be restored to prior condition.  

Schedule and Budget

Highway construction improvements for the project began in mid-2020 and were completed in mid-2022.  The three-year demonstration project is anticipated to begin operations in summer 2022.

Budget for the project is approximately $30.9 million (including $17 million for new Rapid buses). The project is funded by the Federal Transit Administration and TransNet, the regional half-cent sales tax for transportation administered by SANDAG.


KUSI: San Diego transit agencies to begin three-year ‘Bus on Shoulder’ pilot project (6/21/22)

KUSI: Buses will only Enter Shoulder When Travel Lanes operate under 35 MPH (6/21/22)

ABC 10: ‘Bus on Shoulder' Pilot Starts (6/21/22)

San Diego Union Tribune: San Diego’s Bus on Shoulder pilot project launches Tuesday (6/17/22)

Times of San Diego: MTS Buses to Use Freeway Shoulders During Rush Hour in Pilot Program (6/21/22)

Mass Transit: San Diego region’s Bus on Shoulder pilot program driver training begins (12/10/21)

East County Magazine: Bus on Shoulder Training Begins Along Northbound I-805 and Westbound SR 94 Shoulders (12/7/12)

Time of San Diego: 'Bus on Shoulder' Training Begins Along Northbound I-805 and Westbound SR 94 Shoulders (12/7/12)


Project Fact Sheet EnglishEn Español

Frequently Asked Questions English | En Español

Project Map

Charter Memo

Decision Document

Concept of Operations and User Needs

Bus On Shoulder billboard


Weekdays only

5 - 9 a.m. 
(northbound I-805 and westbound SR 94)

3 - 7 p.m. 
(eastbound SR 94 / southbound I-805 connector)

BOS Project Map

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