CLARK — Municipalities that have been honoring police by by painting the center of their main streets with blue lines have hit a do-not-cross line set up by the feds.

Last month, the U.S. Department of Transportation's Federal Highway Administration declared this show of support unsafe because blue lines are meant for marking handicap parking spaces.

"It just made me chuckle that this is what we're worried about in a time when police need our support every day," said Clark Mayor Sal Bonaccorso, who called into Bill Spadea's morning show Friday on New Jersey 101.5.

Clark painted a blue line in September along Westfield Avenue in front of the municipal building and public library.

"When we put the line in, the township was tickled about it," Bonaccorso said. "I just thought that this was hysterical."

An official at the Federal Highway Administration's Office of Transportation Operation cited the Manual on Uniform Traffic Control Devices (MUTCD) for Streets and Highways after Somerset County Engineer Matthew D. Loper wrote the agency in October asking about the practice of painting blue stripes on roadways to support law enforcement.

According to the manual, double lines need to be separated "by a discernible space," and that space "must represent a lack of other markings."

As a result, the federal letter says, "filling in the gap in a double line, either partially or fully, does not comply with the provisions of the MUTCD."

While there are some exceptions, blue is not one of them. According to the manual, the only allowable usage of blue paint on roadways is to differentiate spots for people with disabilities.

"The use of blue lines as part of centerline markings does not comply with the provisions of the MUTCD," the letter says.

It is not clear what the consequences may be for towns that choose to ignore the regulations, but the letter already is putting an end to plans for blue stripes around the state.

Clark Township was one of several to paint a 'Thin Blue Line' to support law enforcement: Courtesy of Clark Township

Union County Department of Engineering Director Joseph A. Graziano Sr. sent a letter to police chiefs in his county alerting them to the regulation.

"With this email I am asking that you have your Municipality remove any colored lines that have been installed between the double yellow or adjacent to a single yellow," he said.

Spadea, who devotes time on his Friday shows to support law enforcement during his weekly #BlueFriday segments, said the regulation was "outrageous."

"I want to see how they can justify there is a safety issue with the blue line," he said. "That is absolutely over-the-top outrageous."

The federal letter said the agency appreciates "the impact of expressing support for law enforcement and value their contributions to society," but that there "are many appropriate and fitting ways to recognize service to the public that do not involve the modification of a traffic control device, which can put the road user at risk due to misinterpretation of it's meaning."

State Department of Transportation spokesman Steve Schapiro said Friday that this was not Trenton's call — it's up to federal authorities.

"NJDOT follows the rules set forth in the federal Manual on Uniform Traffic Control Devices pertaining to any road signals, such as signs and pavement markings," he said Friday.

Contact reporter Adam Hochron at 609-359-5326 or Adam.Hochron@townsquaremedia.com