Internally Illuminated Solar Road Stud Marker with 6 Aluminum . Watch on The recommended spacing between each solar road studs are as follows: Highways and Expressways 7 - 8 yards (5 - 6 meters) Dangerous Entrances and Exits 4 - 5 yards (2 - 3 meters) Access or Exit ways for Hospitals, Parking Lots, etc. 0.5 - 3 yards (0.5 - 2 meters)