Motorists traveling through downtown Hayward this afternoon may face delays because of a protest march planned to commemorate the birthday of Oscar Grant III, who was shot and killed by BART police in January.

Police said they have seen a lot of fliers distributed to announce the march, which begins between 4 and 4:30 p.m., but they do not know how many people will attend. The planned route will start at the downtown BART station, go down A Street, turn on Foothill Boulevard and take B Street to City Hall.

BART spokesman Linton Johnson said it is unclear whether the rally and march will affect transit service.

"I don't know what (the demonstrators) are going to do," he said.

He said additional officers will be at the station "to make sure all our customers get from point A to point B safely."

Organizers and Grant family members said they expect a peaceful march.

Grant, who was shot by a BART police officer at the Oakland Fruitvale station on Jan. 1, would have been 23 today.

Eric Kurhi covers Hayward. Reach him at ekurhi@bayareanewsgroup.com or 510-293-2473.