From the July 17, 2012, Wilmington (NC) Star-News "Back Then" by Scott Nunn.
Wilmington, N.C. was an important arsenal for the war and coastal areas could come under attack by German U-boats, known to lurk off shore, especially in 1942. Besides gas rationing, Wilmington-area residents had further restrictions.
JULY 10, 1942: Brigadier General P.A. Wethered of District 2 Interior defenses announced that motorists along the coast could drive any time of the day or night on unrestricted roads as long as they followed regulations, including a nighttime speed limit of 15 mph and use of parking lights only.
Hey, It Was. --RoadDog