Arlington County pulled three buses from the road on Monday after the brakes on a hybrid bus failed, causing it to roll backward down a hill into other vehicles.

The ART bus, a DesignLine USA model, was headed north on the 45 route along North Barton Street when it started to roll back near Fairfax Drive just before 10:40 a.m.

It ran into one vehicle, causing a three-vehicle chain reaction crash. One person was taken to Virginia Hospital for observation but no others were reported injured. Authorities called the damage to the vehicles "minor."

But the crash closed down Barton Street until 12:45 p.m., according to emergency dispatchers. It also caused immediate safety concerns as the cause was not immediately clear.

The bus, one of three of that model in the county's 44-bus fleet, was new. The county had put the buses into service just nine months ago, so they are still under warranty, said Steve Yaffe, the county's transit service manager. They run as hybrids on electricity from batteries and compressed natural gas. All three buses of that model have been sidelined.

County officials have requested that a detailed forensic analysis be conducted in cooperation with the county and the bus maintenance contractor, National Express, to determine the cause and possible remedies. The manufacturer was also brought on site for the investigation.

Other buses in the fleet will run the routes of the three buses, ART's 45 and 41 lines.

"We won't miss any trips," Yaffe told The Washington Examiner.

But he said the county will have to run 31-foot models that seat 25 passengers in place of the 35-foot models that seat 29. "More people would have to stand during rush hour," said Yaffe. "It's an inconvenience for some people."

The incident was the latest safety problem with local transit buses. Metro pulled 100 of its Orion VI diesel-fuel buses in 2007 after a fire, then again in September 2010 after another fire on Interstate 495. Then in April 2012, the agency sidelined the remaining buses again after two fires within a week.

Montgomery County has also had trouble with fires on its RideOn 2007 Champion/International-model buses. The county ultimately pulled them off the roads last July after at least six fires occurred on that model bus since 2009.