The Mercer Island Park and Ride is not the only overloaded transit lot in the county.

Sound Transit will begin an enhanced parking enforcement program at its Sounder stations and park-and-ride lots in an effort to ensure these popular commuter areas are properly used. The move comes after concerns expressed by Sounder commuter rail and ST Express bus riders that parking is overcrowded as a result of vehicles being parked overnight in lots, as well as other infractions.

Of the 21 transit centers operated by Sound Transit in King, Pierce and Snohomish counties that provide parking, six are at 99 percent capacity or above, and seven are at least 90 percent full.

Sound Transit will provide a one-week grace period for transit lot users. Between Jan. 15 and Jan. 22, warning notices will be given to vehicle owners who park outside the guidelines. Starting Sunday, Jan. 23, cars that either exceed the 24-hour limit or fail to observe other regulations may be immediately towed.