Are you sure they were on I-64 and not I-95 (in VA)? From the Woodbridge exit to Richmond the left lane is for the line of cars that want to pass cars, RV, semis in the center lane driving 5-10 below the posted speed limit. The right lane is often empty and the number of entrance/exits on this stretch are miles apart. When I would travel to VA Beach, I made better time in the right lane (passing those in the center lane) while doing the posted speed limit. This stretch of I-95, during non-rush hours is known as Speed limit-95 vice I-95.
