SCARBOROUGH — Scarborough police are investigating the cause of a tractor-trailer crash that knocked out electrical service to customers and traffic lights in a heavilly traveled retail shopping district near the Maine Mall.

Police said the trailer collided around 5 p.m. with a utility pole near the Lowe’s Home Improvement store at Gallery Boulevard and Mussey Road.

A police dispatcher said the crash knocked out power to a set of traffic lights on Mussey Road and Spring Street. About 150 customers were still without power around 6:45 p.m.

Power should be restored to all customers and traffic lights by 11:30 p.m., a CMP spokeswoman said. The vehicle hit a three-phase pole with multiple circuits, she said, which has lengthened the repair process.

CMP crews are on scene and are in the process of repairing the damaged pole.