Arizona's interstate freeways, including Interstate 40, have posted speed limits of 75 miles per hour. The speed limit is lowered to 65 or 55 miles per hour in metropolitan areas.
The regulation for commercial trucks includes a length of 65 feet, a width of 8.5 feet, and a height of 14 feet with a gross weight of 80,000 pounds. Oversize trucks with transport permits can be up to 120 feet in length, 14 feet in width and 16 feet in height with a maximum weight of 250,000 pounds.
Motorcyclists under the age of 18 are required by law to wear safety helmets and all riders must have some type of eye protection unless a windscreen is used. Other regulations include the use of daytime headlights, at least one mirror on the left or right side, and passenger seats and footrests when carrying a passenger.
