Sometime this fall, depending on the weather, one final dash of green paint will hit the asphalt on a New York City street: the last of the Bloomberg bike lanes.

As the end of Mayor Michael Bloomberg's third term approaches, the Department of Transportation has furiously expanded the city's bike network, with 54.5 miles of bike lanes in planning or under construction this year after 17 miles were added in 2012.

The network has nearly doubled since 2006, to more than 600 bike lane miles citywide, DOT Commissioner Janette Sadik-Khan said.

The question for bike opponents and advocates alike is whether the status quo has changed along with the streets, making the continued expansion of bike lanes an inevitability or a fad that will fade when Mr. Bloomberg is gone.

"In just a few years New York City went from 'bike at your own risk' to becoming the nation's biking capital and a model for other cities," Ms. Sadik-Khan said.