The break occurred around 11:00 p.m. Saturday on Route 202 between Henderson Road and Ivy Lane.
Route 202 was shut down until 11:30 a.m. Sunday while crews worked on repairs.
Around 3:00 a.m. police say a driver came upon the police road block and swerved at the last minute to avoid hitting the Upper Merion patrol car. The vehicle ran off Route 202 and up an embankment. The vehicle then struck a traffic control box knocking out the traffic signal.
The driver was not injured, but was taken into custody and faces DUI charges, according to police.
The break has since been repaired. No word on a cause.