A heavy flow of traffic leaving Maine at the end of Memorial Day weekend caused a backup of 20 miles or more on Interstate 95 in Maine and New Hampshire on Monday, but the congestion eased by late afternoon.

A motor vehicle crash between Exit 19 in Wells and Exit 7 in York early Monday afternoon contributed to the delays on the Maine Turnpike, along with heavy outbound traffic at the tail end of the long Memorial Day weekend, considered the unofficial start to the summer.

The Maine Turnpike Authority issued an advisory in the early afternoon to alert drivers to the heavy and slow traffic in the southbound lanes beginning around Wells and York and continuing into New Hampshire.

That alert was lifted by about 5 p.m., said Erin Courtney, a spokeswoman for the turnpike authority. She said traffic remained heavy, but was no longer backing up.

Some observers and media had reported that the Monday afternoon backup stretched from the Hampton tolls in New Hampshire north into the York area, more than 20 miles away.