DMV Permit Test — Teen Driver Laws and Graduated License Questions

When two vehicles arrive at a four-way stop at the same time, the driver on the right has the right of way. If they arrive at different times, the first to stop goes first. If three or four vehicles arrive simultaneously, the standard rule is still 'yield to the right', though in practice drivers often resolve the situation by eye contact and one driver waving the other through. Right-of-way rules are 'yielding' rules: they tell you who must wait, not who absolutely must go. A driver who legally has right of way should still yield when needed to prevent a crash. Vehicles going straight typically have right of way over those turning left at signal-less intersections, but the same-arrival-time rule still defers to the right.

A yellow (amber) traffic light means the signal is about to turn red and you should stop if you can do so safely. The yellow signal exists to give drivers time to clear or stop at the intersection — it is not an invitation to accelerate. The decision is judgment-based: if you are far enough from the intersection that you can stop without hard braking, do so. If you are so close that stopping would require slamming the brakes and possibly being rear-ended, proceed cautiously through. Speeding up to beat the light is dangerous because cross-traffic begins entering the intersection as soon as the light turns red. Some intersections also have red-light cameras that ticket vehicles entering after the light turns red.

When you see or hear an emergency vehicle (police, fire, ambulance) approaching with siren and/or flashing lights, pull over to the right edge of the road as soon as it is safe and stop. Remain stopped until the emergency vehicle has passed. On a divided highway, only vehicles traveling in the same direction must yield. At an intersection, do not block the intersection — clear it before stopping if possible. Stopping immediately in the middle of the road, or in the left lane, blocks the emergency vehicle's path. Speeding up to 'get out of the way' is dangerous: emergency drivers expect you to pull over, not to race ahead. Following an emergency vehicle (chasing) within several hundred feet is also illegal.

The standard rule is a 3-to-4-second following distance under good conditions. You measure it by picking a fixed point on the road (a sign, a tree), starting to count when the vehicle ahead passes it, and counting until you pass it: 'one one-thousand, two one-thousand, three one-thousand'. If you reach the point before you finish counting to three, you are following too closely. Increase to 4 or more seconds in rain, fog, snow, on slick surfaces, when towing a trailer, or when behind a large truck whose rear blocks your view. One- and two-second following distances are dangerously close: at highway speed, a one-second gap is only about 90 feet, far less than a typical braking distance.

The 'basic speed law' (or 'reasonable and prudent' law) requires drivers to operate at a speed that is reasonable and safe for current conditions — even if that speed is below the posted limit. In rain, fog, snow, heavy traffic, or other hazardous conditions, the safe speed is below the posted limit. A driver can be ticketed for driving 'too fast for conditions' at a speed lower than the posted limit. The posted limit is a maximum for ideal conditions, not a target for all conditions. Conversely, you may not exceed the posted limit even if you feel conditions allow it; the posted limit is also a legal maximum. This dual standard means drivers must use judgment as well as obey signs.

On a multi-lane road, the right lane is for normal driving and the left lane is for passing. The 'keep right except to pass' rule reduces lane-changing and the conflicts it creates. Slow vehicles in the left lane disrupt traffic flow and force faster traffic to pass on the right, which is more dangerous than passing on the left. Some states fine drivers for camping in the left lane. The middle lane (on three-lane roads) is for through traffic going at the normal flow. Always use the right lane for slow driving, when towing, when leaving the highway soon, or when other traffic is faster than you. The 'fast lane' is not a privilege earned by who can drive there fastest; it is a passing lane.

Safe passing on a two-lane road requires: (1) checking that the oncoming lane is clear for the full distance needed to complete the pass and return to your lane safely — typically 700 feet or more at highway speed; (2) checking your mirrors and blind spot for vehicles already passing you; (3) signaling your intent; (4) moving into the oncoming lane and accelerating to clear the slower vehicle; (5) signaling and returning to your lane only after you can see the slower vehicle in your rearview mirror. Never pass where road markings prohibit it (solid yellow line on your side), near intersections, on curves, on hills, or where you cannot see the road ahead clearly. Honking before passing is sometimes appropriate but does not substitute for clear line of sight.

Yellow lines separate traffic moving in opposite directions. A solid yellow line on your side of the centerline means passing is prohibited from your side — it is unsafe to cross into the oncoming lane to pass. A broken yellow line on your side means passing is permitted when the oncoming lane is clear. Two solid yellow lines (a double solid) means passing is prohibited in both directions. White lines separate lanes moving in the same direction; a broken white line means lane changes are permitted, and a solid white line discourages but does not always prohibit lane changes (laws vary). Markings are placed by traffic engineers based on sight distance and road geometry — they exist to keep you alive.

Most states require you to signal at least 100 feet before a turn or lane change in a residential or city area, and longer (sometimes 200 feet) on highways. The point of signaling early is to give other drivers, cyclists, and pedestrians time to react — to slow, to clear the lane you are moving into, or to anticipate your maneuver. A last-second signal provides almost no warning. Signaling 'just in case' someone is in a blind spot is a habit that keeps you safe even when you cannot see other traffic. After completing the turn or lane change, cancel the signal so it does not mislead other drivers. Even on empty roads, the habit of signaling correctly is what keeps you doing it right when it matters.

In every US state, the per se blood alcohol concentration limit for drivers age 21 and older is 0.08%, except in Utah, which lowered it to 0.05% in 2018. A BAC at or above the limit is itself a violation regardless of how impaired you appear — 'per se' means the BAC alone proves the offense. Drivers under 21 face stricter limits (zero tolerance to 0.02% depending on state) because the legal drinking age is 21. Commercial drivers face a 0.04% limit when operating a commercial vehicle. Note that impairment begins well below the legal limit: most drivers show measurable degradation in driving ability at BACs as low as 0.02%. The legal limit is the threshold at which you are presumed too drunk to drive; you can be charged with impaired driving below the limit if your driving demonstrates impairment.