A.R.S. § 28-701: Basic Speed Law

28-701. Reasonable and prudent speed; prima facie evidence; exceptions

A. A person shall not drive a vehicle on a highway at a speed greater than is reasonable and prudent under the circumstances, conditions and actual and potential hazards then existing. A person shall control the speed of a vehicle as necessary to avoid colliding with any object, person, vehicle or other conveyance on, entering or adjacent to the highway in compliance with legal requirements and the duty of all persons to exercise reasonable care for the protection of others.

B. Except as provided in subsections C and D of this section or except if a special hazard requires a lesser speed, any speed in excess of the following speeds is prima facie evidence that the speed is too great and therefore unreasonable:

1. Fifteen miles per hour approaching a school crossing.

2. Twenty-five miles per hour in a business or residential district.

3. Sixty-five miles per hour in other locations.

C. The speed limits prescribed in this section may be altered as authorized in sections 28-702 and 28-703.

D. The maximum speed provided in this section is reduced to the speed that is reasonable and prudent under the conditions and with regard to the actual and potential hazards then existing, including the following conditions:

1. Approaching and crossing an intersection or railroad crossing.

2. Approaching and going around a curve.

3. Approaching a hillcrest.

4. Traveling on a narrow or winding roadway.

5. A special hazard exists with respect to pedestrians or other traffic or by reason of weather or highway conditions.

E. A person shall not drive a motor vehicle at a speed that is less than the speed that is reasonable and prudent under existing conditions unless the speed that is reasonable and prudent exceeds the maximum safe operating speed of the lawfully operated implement of husbandry.