Brooklyn state Sen. Marty Golden tried to pull over a bicyclist by impersonating a cop — and then his wheelman ran a red light and drove into oncoming traffic to get away when the cyclist snapped the pol’s picture, according to the cyclist.

Brian Howald, a transit advocate and member of Brooklyn Community Board 2’s Transportation Committee, was pedaling down Third Avenue to attend a neighboring community board’s meeting Monday night when Golden accosted him, he said.

Howald was heading south in the bike lane when a late-model Cadillac SUV trying to get around traffic entered the bicycles-only lane behind him. Howald refused to give up his space, and the car re-entered the traffic lane and pulled alongside him moments later.

That’s when Golden, who was riding shotgun, leaned out the window waving what appeared to be a parking placard and claiming he was a police officer.

“He said that he was a police officer and repeated his demand for me to pull over and waved what appeared to be a laminated placard,” Howald told The Post Tuesday. “I reiterated that I was in the bike lane and he said he was going to take me to the precinct. I asked what precinct, and he refused to answer and called me an a–hole.”

Howald almost left it at that, but quickly realized the placard did not bear an NYPD shield and decided to try and take Golden’s picture so he could alert authorities that the man was possibly misrepresenting himself as a police officer.

Golden is a former NYPD cop who retired in 1983 on disability after being injured in a drug-related arrest.

Howald attempted to film Golden, but the senator’s unidentified driver gave him the slip by driving south in a northbound lane on Third Avenue to get around traffic, Howald said.

The cyclist later caught up to the car at a red light as it was turning onto 19th Street from Third Avenue.

“I asked [Golden] who he was, to which he responded ‘Wouldn’t you like to know,’” Howald said. “As soon as there was a break in the traffic heading north on Third Avenue, the driver took off through the red light.”

Howald encountered the vehicle one more time on 4th Avenue and 34th Street. He says he was not following the car — rather that was the route he would normally take to the Community Board 7 office on Fourth Avenue.

Howald does not know for certain the man in the car was Golden, but an Albany insider says the vehicle belongs to the state senator.

Photos shot by Howald also show that the man who appears to be Golden is wearing the same blue dress shirt with a white collar and distinctive plaid tie that Golden wore in photos posted to the senator’s Twitter page on Monday.

Golden did not respond to repeated calls and an email seeking comment.

The vehicle’s license plate number, which the Post is not publishing, is associated with more than 30 traffic violations over the last four years — including for running red lights, not feeding parking meters, standing in bus stops and for speeding in school zones, according to city records.

Seven of Golden’s 10 school-zone speeding violations happened near schools in his Senate district, records show.

“Anybody who drives like that should not have a driver’s license,” Howald said.

Golden has strongly opposed efforts in the state legislature to expand the number of speed cameras used on city streets.

Golden also ran over a 74-year-old woman in September 2005, an incident he called “devastating” and for which he was not charged because investigators determined the woman was crossing against the light. She died five months later.

Ironically, Golden sponsored never-passed legislation in 2015 to “add bicycle and pedestrian safety to the driver’s education course taught throughout the Empire State.”