 We're checking Route 4 north out of Upper Marlboro. The northbound lanes were still closed at last report. Between Dower House Road and Suitland Parkway, Presidential Parkway, this is a longstanding police investigation from an early morning crash. Celebrate July 4th with savings at Lowe's from plants to paint. Save on summer essentials for all your seasonal celebrations. Mary DePompa, WTOP Traffic.