The dreaded 15-month L train shutdown is a little more than a year away, and residents are scrambling to put together a plan to mitigate the impacts that it will have on hundreds of thousands of New York City straphangers. The MTA has already released a preliminary strategy, which includes increased service and capacity on a variety of subway lines that run through Brooklyn, expanded bus service in the impacted areas and a handful of infrastructure changes—but there is a general sense that they do not go far enough.

When the shutdown was first announced in 2016, the Van Alen Institute held an event in which 33 design teams pitched a series of outlandish transit alternatives for passage across the East River. And last week, another group floated another proposal that might just be crazy enough to work: a pontoon bridge.