What's the Same on Every State's DMV Test — and What Isn't

Every state writes its own driver handbook and its own knowledge test, but most of what those tests ask is the same everywhere. Road signs, pavement markings and traffic signals follow one federal standard, and the basics of right of way and safe driving don't change at a state line. A smaller set of rules is genuinely state law. Knowing which is which tells you where any practice test can be trusted as-is, and where you have to read your own state's handbook.

The same in every state

These come from the federal Manual on Uniform Traffic Control Devices (MUTCD), which every state follows, or from driving practice that no state disputes.

Road sign shapes and colors: An octagon always means stop and a downward triangle always means yield. Yellow diamonds warn of hazards ahead, orange signs mark work zones, green signs give directions, blue signs point to services and brown signs to parks and recreation. A yellow pennant on the left side of the road marks a no-passing zone, and a round yellow sign warns of a railroad crossing ahead.
Pavement markings: Yellow lines separate traffic moving in opposite directions; white lines separate traffic moving the same way. A solid line means don't cross it to pass; a broken line means you may cross when it is safe. With a solid and a broken line side by side, you may pass only from the side with the broken line.
Traffic signals: Steady red means stop, steady yellow means the light is about to turn red, and green means go if the way is clear. A flashing red light is treated like a stop sign and a flashing yellow light means proceed with caution. When a signal is dark, treat the intersection as an all-way stop.
Core right of way: Yield to pedestrians in crosswalks. At an all-way stop the first driver to arrive goes first, and if two arrive together the driver on the left yields to the driver on the right. Turning left, yield to oncoming traffic. Entering a roundabout, yield to traffic already in it. For an approaching emergency vehicle with lights and siren, pull to the right and stop.
Railroad crossings: A crossbuck is a yield sign for the railroad. Never drive around lowered gates, never start across unless there is room for your whole vehicle on the other side, and if the lights keep flashing after a train passes, wait — another train may be coming.
Alcohol and your body: Only time lowers your blood alcohol. Coffee, food, a cold shower and fresh air do nothing. Alcohol affects judgment before it affects coordination, which is why a driver who has been drinking usually feels safer than they are.

Set by your state — check your handbook

These are where practice tests, including ours, can't give one answer that is right for everyone. If a question turns on one of these, the answer in your state's handbook is the one that counts.

The adult alcohol limit: The per se limit for drivers 21 and over is 0.08 in every state except Utah, where it is 0.05.
The under-21 alcohol limit: Every state has a zero-tolerance law for drivers under 21, but the exact threshold differs: some states set it at 0.00, others at 0.01 or 0.02.
Right turn on red: Allowed after a complete stop in most places unless a sign says otherwise, but some cities ban it outright — New York City is the best-known example.
Left turn on red: Rules vary. Many states allow it only from a one-way street onto another one-way street; some also allow it onto a one-way street from a two-way street; some don't allow it at all.
School buses on divided roads: Traffic behind a stopped school bus with its red lights flashing must stop everywhere. Whether traffic coming the other way must also stop depends on the type of road and on your state's law.
Curb colors: Painted curb colors are not a federal standard. Some states, California most prominently, give each color a legal meaning; many states don't use them at all.
Parking distances: How close you may park to a fire hydrant, a crosswalk, a stop sign or a railroad crossing is set by each state, and the numbers differ.
Following distance: Handbooks teach a time gap rather than a distance, but they don't all use the same number of seconds, and many ask for more in bad weather or behind large vehicles.
Speed limits: Default limits for residential streets, school zones, rural highways and freeways are all set by the state.
New-driver rules: The age you can get a permit, how long you must hold it, supervised-driving hours, night-time curfews and passenger limits for new drivers vary widely between states.
Phones, headlights and move-over details: Which phone uses are banned while driving, whether headlights must be on whenever your wipers are, and exactly which roadside vehicles a move-over law covers are all state law.

A good rule of thumb: if the answer to a practice question is a number — a distance, an age, a time, a blood alcohol level — check it against your own state's handbook before test day. Our state pages keep those rules state-specific instead of giving them one national answer.

Written by Drive To Excel DMV, an independent study site not affiliated with any state DMV. Always confirm requirements with your state's DMV.