SAN FRANCISCO (CBS SF) — A man died when he lost his balance and fell off a bike between two westbound Municipal Railway buses Sunday afternoon in San Francisco, spokespersons for the police and the San Francisco Municipal Transportation Agency said.

The first report of the collision came in at 3:23 p.m. in the 500 block of Market Street, according to police.

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The man, 48, died when he went under one of the bus tires, police spokeswoman Officer Grace Gatpandan said.

She said police have made no official decision on who was at fault in the death.

Officers will be reviewing surveillance video and witness statements and taking into account factors such the as time of day and road and weather conditions before making a decision, she said.

Gatpandan said officers will conduct a thorough investigation because “the victim can’t speak for himself.”

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SFMTA spokesman Paul Rose said the bus driver will undergo drug and alcohol testing and SFMTA officials will be working with police to determine how the collision occurred.

Agency officials will review video from other buses nearby as part of that investigation, Rose said.

A separate incident involving a bike occurred a little later in the afternoon along The Embarcadero, Gatpandan said.

A woman suffered injuries not considered life-threatening when a southbound truck trailer struck her at 4:01 p.m. as she was riding a bike at the intersection of The Embarcadero and Chestnut Street, Gatpandan said.

The woman was taken to a hospital for treatment, she said.

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