NEW YORK - New signs have been installed along the FDR Drive in Manhattan to remind drivers that only passenger vehicles are allowed on parkways.

The bright red markers read "All Trucks Must Exit".

The goal is to reduce the number of trucks that strike overpasses.

New markings have also been painted onto the roadway to warn of low clearance.

"The FDR moves thousands of motorists each and every day. Unfortunately, we do have trucks and even tractor trailers who inadvertently wander onto this roadway. Thus, creating a hazard to other drivers and potentially damaging the overhead structures," said NYPD Chief of Transportation Thomas Chan.

"We're going to put those at critical locations along the parkway at the Harlem River Drive, 155th street, 116th street, and 106th street," said DOT Commissioner Polly Trottenberg. 

Truck strikes are the third most common cause of bridge failure.

The city says there have been five so far this year.