Traffic Laws and Rules of the Road
Core concepts
Arizona drives on the right, and the basic speed rule governs every road: never faster than is safe for conditions, regardless of the posted limit. Know the default urban limit (25 mph), rural limit (65 mph on most highways unless posted), and school-zone behavior, which is posted and enforced when children are present or as signed. Right-of-way is never "taken"; it is yielded. At an uncontrolled intersection, the first vehicle to arrive goes first; if two arrive together, the driver on the left yields. A vehicle turning left across oncoming traffic yields to that traffic, and a driver entering a roadway from a driveway, alley, or private road yields to all traffic already on the road.
Signals and turns
Signal at least 100 feet before a turn and well before lane changes. Left turns go from the leftmost lane into the corresponding lane; right turns stay close to the right curb. U-turns are restricted where signs prohibit them and on curves or crests where visibility is limited. Passing is legal only when you can see clear roadway and complete the maneuver safely; never pass on a solid yellow line, at a railroad crossing, or where a sign forbids it.
Traps
Questions love absolutes: "always," "never," and "the right-of-way." Remember that a green light means proceed only if clear, and that a driver already in an intersection when the light changes may finish crossing. School buses with flashing red lights require a stop from both directions on undivided roads; on a divided highway, oncoming traffic need not stop. Do not confuse a flashing yellow arrow (yield, turn when clear) with a solid yellow light (prepare to stop).
Rule of thumb
At a four-way stop, count arrival order, not vehicle size: first in, first out; ties go to the right. When in doubt, yield.