The northbound lanes between exits 4 and 5 in Bridgeport and between exits 5 and 8 in Trumbull are closed, the state’s transportation agency said early Tuesday. The Department of Transportation said it learned of a crash in Trumbull about 3:30 a.m. and was alerted to a road closure in Bridgeport about 4 a.m. It wasn’t clear early Tuesday if there was one crash or two.