It started as a normal date night: Shawn, a bearded graduate student who favors lumberjack plaid, went to Williamsburg for dinner and drinks with his girlfriend. But instead of taking the L train from their Chelsea apartment, they decided to ride Citi Bikes there and back.

A couple of cocktails at the Wythe Hotel led to beers at Mable’s Smokehouse and a nightcap at Post Office, a dive-like whiskey bar. After four or five drinks, they undocked a pair of blue bikes and rode home over the Williamsburg Bridge.

As usual, Shawn sped ahead, and as they ascended over the East River, he turned around to see where his girlfriend was. That’s when he lost his balance, kicked his foot into a bridge railing and broke his toe.

“I really wasn’t that drunk,” said Shawn, 30, who uses the bike-share program about 20 times a week. (Shawn, like many of the people interviewed, asked that his full name not be used; drinking and cycling is not really something to toot your bike horn about.) “I’ve never blackout Citi Biked.”