AC Transit plans to add a Rapid Transit bus line set up in the median of International Boulevard running from Oakland to San Leandro.
Demonstrators blocked traffic and parking at 20th Avenue and International Boulevard on Tuesday afternoon.
They said the project will eliminate hundreds of parking spaces and congest the area by eliminating two lanes of traffic.
"I'm in the middle of the street. I rely on parking. I rely on drop offs," Manuel Romero said.
"If customers can't come to my store freely and not drive around for 15 to 20 minutes looking for parking, stuck in traffic, they're going to go somewhere else," Allen Nguyen said.
The project will cost $200 million. Shop owners say for an additional $6 million, the plan can be changed to help mitigate the damage to their businesses.
Construction will begin next year with service starting in 2017.