Skip to Content
Streetsblog New York City home
Streetsblog New York City home
Log In
Brooklyn

Eric Gonzalez Convicts Drunk Driver of Manslaughter for Killing Cyclist on Gerritsen Avenue

DOT installed a bikeway and other safety measures after a drunk driver killed Sean Ryan on Gerritsen Avenue. Photo: DOT

A motorist has pled guilty to manslaughter for killing a cyclist on Gerritsen Avenue in Brooklyn.

Sean Ryan, 17, was riding on Gerritsen near Florence Avenue on the night of July 17, 2016, when Thomas Groarke, driving the opposite direction in a Honda sedan, crossed the center median and hit him head-on, according to the office of District Attorney Eric Gonzalez.

Sean Ryan
Sean Ryan
Sean Ryan

Groarke, who had four passengers in the car after a day of drinking at a Staten Island bar, was attempting to pass another vehicle at 80 miles per hour when the collision occurred, the DA's office said. Ryan died instantly.

Groarke had a blood alcohol level of .14 two hours after the crash. He was charged by the late district attorney Ken Thompson with manslaughter, homicide, DWI, and other charges.

Last March, Groarke, 26, entered a guilty plea to second-degree manslaughter, “which was offered by the Court over the prosecutor’s objection,” Gonzalez’s office said. This week he was sentenced to three to nine years in prison.

“This defendant’s reckless and criminal driving took the life of a promising teenager who was doing nothing more than riding his bike," Gonzalez said in a statement. "I am determined to continue prosecuting dangerous motorists who kill others on Brooklyn’s roadways, which should be safe for everyone who uses them.”

At the time of the crash, Gerritsen Avenue was a speedway with a history of deadly crashes. After Ryan was killed, DOT installed a protected bike lane, pedestrian islands, floating bus stops, and other measures to slow motorists down.

Stay in touch

Sign up for our free newsletter

More from Streetsblog New York City

Streetsblog Celebrities Reveal Their Mayoral Rankings!

Who did the legends of the livable streets movement rank for mayor? Click to find out — plus find out who wins their ranked choice vote!

June 19, 2025

Black Cycling Clubs: ‘We Just Want a Safe Place to Park Our Bikes’

Leaving a bike on the sidewalk overnight or while at work often results in a missing tire or gearset, but for most of us, it’s only a matter of time until the entire frame disappears. 

June 19, 2025

Congestion Pricing Is Cutting Traffic Jams In New York AND New Jersey: Research

Travelers in Manhattan's central business district — and even those far beyond it — have gotten back tens of thousands of hours thanks to fewer traffic jams.

June 18, 2025

BREAKING: Judge Halts Mayor’s Plan to Tear Out Bedford Av. Bike Lane

And now the city will have to persuade a judge that officials weren't acting "arbitrarily, capriciously, and illegally" in ordering the hasty removal.

June 18, 2025

Small ‘Wonder’: Delivery Workers Protest Deactivations By New Food App Power Player

More than 50 delivery workers have had their accounts deactivated by Grubhub in the past two weeks — and they're blaming the company's new owner, a booming new player called Wonder. 

June 18, 2025
See all posts