Ariz. Rev. Stat. § 28-952
A. The following brake equipment is required:
5. In any combination of motor drawn vehicles, means shall be provided for either or both of the following if capable of being used alternatively:
6. A motor vehicle and combination of vehicles manufactured or sold in this state after July 1, 1964, except motorcycles, all-terrain vehicles and motor driven cycles, shall be equipped with parking brakes that are:
B. At all times, under all conditions of loading, on a dry, smooth, level road free from loose material and on application of the service or foot brake, a motor vehicle or combination of motor drawn vehicles shall be capable of being stopped within the distances specified below or of being decelerated at a sustained rate corresponding to these distances:
Feet to stop Deceleration
from 20 miles in feet
per hour per second
Vehicles or combinations of
vehicles having brakes on
all wheels 30 14
Vehicles or combinations of
vehicles not having brakes
on all wheels 40 10.7