 It runs parallel to I-68 through northern Garrett County as a two-lane road with truck lanes on some uphill sections.The annual average daily traffic (AADT)—that is, the number of cars that use the road per day, averaged over the course of one year—is 1,831 at the western end of Alt US 40.For comparison, the parallel section of I-68 has an AADT of 14,271.