The U.S. Postal Service (USPS) is claiming it is not liable for red light traffic violation fines incurred by its employees, Associate Dean Daniel Filler explained to CBS Philly.

According to the article, American Traffic Solutions (ATS), the company that manages Philadelphia's red light cameras has attempted to collect payment on traffic ticket violations issued against USPS trucks.  However, USPS has refused to pay saying it is not liable for its employees' traffic fines.

This is a consequence of using advanced technology to issue tickets, Filler said.  In instances where you are issuing tickets to vehicles and not directly to drivers, you run the risk of giving "a ticket to someone who doesn't have a legal responsibility to pay it," he said.  By claiming immunity, USPS is saying that local authorities should bear the cost of collection from drivers, not USPS, Filler concluded.

Filler, a former public defender, studies the effects of social anxiety on the development of criminal law.