Danica Helb, a 35-year-old scientist and researcher at the University of California in San Francisco, was riding her bike on 16th Street Tuesday afternoon from her lab at San Francisco General Hospital to her office in Mission Bay, something she’s done three times a week for the past six years.

Between Mississippi and Owens, the traffic lanes narrow and “you lose the designated bike lane and there’s no shoulder,” she explained. That’s where a black Cadillac squeezed past at high speed within “six inches,” she said. That, despite the fact that there was ample space in the next lane and several other cars had just passed safely.

The incident left her shaken, so she glided a few car lengths ahead to where the Cadillac had stopped at a red light. She knocked on the window. The driver said “Go away, I’m not talking to you.” Helb replied: “Excuse me, you have to give cyclists three feet when passing, please be more careful.”

At that point the driver, whom Helb described as an African America woman, 45-to-55, and heavy set, started screaming. She rolled down the window and shouted “You better get out of here!” as she pulled out a spray can. Helb backed off. But the driver sprayed anyway. She dodged most of the orange mist, but the wind managed to waft some of it towards her. “It got into my throat and eyes,” she said. But she managed to get a photograph of the license plate.

Two witnesses came forward and gave Helb contact information. One of them, who asked only to be identified as Sarah, spoke with Streetsblog. “The cyclist was really shaken up and surprised,” she said. “It was unwarranted the way she was treated by the person in the vehicle.”

Unwarranted and illegal, stressed Andy Gillin, an attorney with the Bay Area firm GJEL. “It could well be a felony. It’s at least a misdemeanor assault,” he said.

The question is, will the San Francisco Police treat it as such?

Helb filed a police report. Carlos Manfredi, a spokesman for SFPD, said an inspector is assigned to the case and will start investigating. “He will reach out to the victim, get more details, reach out to the witnesses as well,” he said.

But going by past experience, Chris Cassidy, a spokesman for the San Francisco Bicycle Coalition, doesn’t have confidence. “The SFPD’s leadership can find hundreds of officer-hours for cracking down on people biking. When you hand the SFPD witnesses’ accounts and license plate numbers, however, they can’t find the time to investigate allegations of assaults against SF Bicycle Coalition members like Danica Helb and Maxwell Wallace ,” he said.

Gillin, meanwhile, said the way to make sure the police investigate is to bring the incident to the attention of bike-friendly San Francisco Supervisors, which Streetsblog did. “We expect SFPD to investigate allegations of assault in all its seriousness, regardless of whether the charge comes from a bicyclist, a car driver, or anyone,” said Ivy Lee, a spokeswoman for Supervisor Jane Kim. “That’s their job and they should do it.”

Manfredi said that’s what’s happening. And while he recommends against confronting drivers, he praised Helb. “She was right to get the license plate and witnesses.”

Helb, meanwhile, said she’ll continue to bike to her appointments. “It’s important to let drivers know when they’re being unsafe,” she said, adding “I’m still going to call them on it.”

Note: GJEL is a Streetsblog sponsor.