App senses potholes, alerts city officials BOSTON - When your car hits a pothole, a new technology could help you immediately tell someone who can do something about it. Boston officials are testing an app called Street Bump that enables drivers to automatically report the road hazards to the city as soon as they hear that unfortunate "thud," with their smartphones doing all the work. The app's developers say their work has already sparked interest from other cities in the U.S., Europe, Africa and elsewhere that are imagining other ways to harness the technology. Before they even start their trip, drivers using Street Bump fire up the app, then set their smartphones either on the dashboard or in a cup holder. The app takes care of the rest, using the phone's accelerometer - a motion detector - to sense when a bump is hit. GPS records the location, and the phone transmits it to remote servers hosted byAmazon.com Inc.'s Web services division. The system filters out things like manhole covers and speed bumps using a series of algorithms - including one that can tell if the initial motion is up over a speed bump, as opposed to down into a pothole. If at least three people hit a bump in the same spot, the system recognizes it as a pothole. As in many northern cities, potholes are a real problem for Boston. Crews patch about 19,000 of them a year after the annual freeze-thaw cycle, according to Matthew Mayrl, chief of staff in the city's Public Works Department. "You can imagine that driving 806 miles of roadway and getting an accurate count of where every pothole is is a gigantic task," he said. City officials hope the app might eventually help them save money by creating a real-time map of potholes that need to be fixed and eliminating the need to troll the roads looking for damage. "What this technology allows us to do - because we imagine dozens and hundreds and possibly thousands of people using it - it essentially creates a new way for people to donate their data in solving public-good challenges," said Nigel Jacob, co-chairman of the Boston Mayor's Office of New Urban Mechanics, which manages the project. Street Bump is different from Boston's first app, Citizen Connect, which required users to actively send a text or tweet, visit a website or call a 24-hour hotline to report a pothole or other nuisances. Other cities - including San Francisco; Honolulu;Washington, D.C.; and Columbus, Ohio - have encouraged residents to report potholes using Facebook, Twitter, or special apps that enable them to request city services using their smartphones. Street Bump became available free of charge in the iTunes store in June. An Android version is in progress. Jacob said "a couple of hundred" users have downloaded the app so far, and developers are still trying to figure out how many will be needed to make the software more useful. The project's next big phase, he said, will be expanding the app to other cities in a couple of months and beginning to analyze the data to figure out ways to refine the app.