Look both ways

It was set to begin Monday before a lastditch legal appeal postponed it Friday: For most of the time, most of Manhattan’s 14th St., a vital thoroughfare, will be reserved for buses and bicycles. This is fine. Cars will still be able to use the street for a block or two to pick up and drop off passengers; trucks can do the same to make deliveries. Other than that, they must turn off (right-turns only).

Legal challengers should stand down. We welcome the Department of Transportation’s openness to rethinking one street among thousands to prioritize mass transit and bicycles — provided there’s an honest, real-time reckoning with the results. (This is a job Mike Bloomberg’s DOT, which made big changes of its own, frequently fell down on.)

Among the indicators the DOT under Polly Trottenberg must monitor and publish when the plans finally get up and running:

• Buses now creep along 14th St. at 4.5 miles an hour, which is slower than many people walk. Will they get faster? If so, how much?

• What happens to bus ridership, which has dropped dramatically over the last 10 years?

• What happens to bicycle traffic on the street? Pedestrian safety?

• When cars can no longer go east or west, does that wind up jamming surrounding streets, many of which are quieter and more residential, with more car traffic? If it spikes, what are the consequences?

• Finally: Businesses along the stretch, many of which are already in a tightening vise thanks to rising labor costs, rents and property taxes, worry that barring cars will drive customers away. We think that’s unlikely in the heart of Manhattan, but it could happen.

Judge success or failure by evidence. And scrap the plan if it’s not working.