Officials in Detroit are launching a new schedule they say will keep buses in the city running on time on selected routes. The Detroit Department of Transportation is creating a so-called four-fifteen plan – vowing to have buses on four of the city’s busiest routes arrive at stops every 15 minutes between six in the morning and six at night. Those routes include the Dexter, Grand River, Gratiot and Woodward lines – which officials say carry more than one-third of all the systems’ ridership. The move is part of the city’s plan to focus on the most-used routes and eliminate others in order to help close Detroit’s budget deficit. Mayor Dave Bing says the system continues to show improvement.