The Broadway line will only work if the buses above it change too

The tunnel is dug, the schedule is beaten, and the region is entitled to a week of feeling good about a megaproject that behaved. Then it should look up from the tunnel to the street, because the next decision is quieter and arguably larger: what happens to the buses.

The 99 B-Line — the workhorse the subway replaces — is only the most famous route in a web that was designed around its absence. The corridor's riders do not appear at stations by teleportation; they arrive on the north-south routes, whose frequencies were set in an era when Broadway was where buses went to be stuck.

The temptation, already visible in the service plans, is to bank the subway's capacity as savings — trim the parallel service, hold the feeders flat, and let the new line absorb the region's growth on its own. That is how cities turn a generational investment into a full train that people drive to.

The alternative costs money but not much of it, by megaproject standards: pour the B-Line's service hours into the feeder grid, and let the subway do what spines do — carry what the limbs deliver. The tunnel took eleven years of argument. The bus map will take one budget season, and it will decide what the tunnel was for.