“That needs to change. I stand ready to work with community members and other elected officials to change the law so that drivers who kill or gravely injure others no longer enjoy impunity.”

New York has a raft of laws around traffic violations, but prosecutors and defense lawyers say drivers who cause fatalities are almost never criminally charged, unless there are aggravating circumstances: if the driver was under the influence of alcohol or other substances; intended to harm someone; or was aware of the risk of harm, but chose to ignore it.

Running a red light alone is almost never considered reckless driving, even though in Mr. Alzorriz’s case, it had fatal consequences.

“If you’re not drunk and you stay at the scene, it’s very unlikely that anything is going to happen to you,” said Jon Orcutt of Bike New York, an advocacy group, and the former director of policy at New York City’s Department of Transportation.

“You have penalties in society in order to create a deterrent,” he said. “But I don’t think we’re doing that with regard to how people drive in the city.”

Failing to yield to pedestrians and cyclists, a common cause of accidents, carries a penalty of up to $750. The practice of opening a door in the path of a moving cyclist or car — so-called dooring — is illegal, but carries just a $150 fine. Last month, Em Samolewicz was killed while riding her bike after a driver opened the door of his van into traffic, causing her to crash and tumble. A tractor-trailer ran over her.

To date, only one vehicle-related cyclist death has reached the trial stage. Last October, a bus driver was found guilty of killing a cyclist after a bench trial in State Supreme Court in Manhattan. The judge convicted the driver of failing to yield the right of way, a misdemeanor, and failure to exercise due care, a violation.