MILWAUKEE. Starting next spring, two of Milwaukee's busiest corridors will be free to ride for twelve months, in a pilot designed to test whether removing fares lifts ridership and cuts the cost of collection.

Transit advocates called it a once-in-a-generation experiment. Critics worry about the revenue gap, which the county says it will close with a combination of state funds and advertising.

The buses run empty less often than you think. The question is whether the city is willing to treat mobility as infrastructure rather than farebox.