Starting today, drivers headed eastbound on Market Street will have to detour around stretches of the thoroughfare.
The plan is part of a study that will examine limiting personal vehicles and boosting transit service and pedestrian usage along Market Street.
Eastbound drivers will be encouraged to turn right off Market Street at 10th Street, but will be forced to do so at Eighth Street. Vehicles that turn right on Market Street from Seventh Street will be pushed back off to Sixth Street.
Muni, taxis and delivery vehicles will be exempt from the required right turns.
The trial period will last six weeks. Full implementation of changes on Market Street is scheduled to begin in 2013, after input from the community and an environmental review.