Do Electric Bikes Belong in NYC?

Photo: City Room

In its most recent installment, the City Room bike column cites the apparently burgeoning popularity of electric bicycles. According to the story, "e-bikes" are favored by delivery workers, the elderly, and at least one 38-year-old Manhattan screenwriter. Thing is, it's illegal to ride them in the city:

Sellers and riders are hoping state law will be amended soon, but is that a good idea? At the recent Upper East Bike forum, Council Member Daniel Garodnick said he is authoring a bill to increase penalties for riding motorized bikes on sidewalks, which he believes is occurring more often.

Weighing the possible pros (increased mobility for those who can't ride regular bikes) and cons (potentially dangerous pedestrian conflicts), do motorized bikes capable of traveling 20 mph have a place in the city's transportation mix? If so, where do they belong?