DMV PracticeWhy rules differ from state to state
A driver licensed in one state may drive in all of them, yet each state writes its own traffic code. Here is what stays the same and what changes.
Who makes the rules
Traffic law in the United States is mostly state law. Each state legislature passes its own vehicle code, and the state's licensing agency writes the handbook and the test from it. Virginia's manual says so directly: it is a general guide and not a substitute for the Code of Virginia.
What is the same almost everywhere
Signs and signals follow national standards, so a stop sign or a yellow line means the same in every state. The three handbooks we read also agree on these:
- A speed limit is a maximum for good conditions; you must slow down when conditions are poor.
- Following distance is measured in seconds.
- Signal about 100 feet before turning.
- Yield to traffic already in a roundabout.
- An adult driver is over the alcohol limit at 0.08 percent.
- Headlights are on from sunset to sunrise (Virginia and Oregon state this; we did not capture California's wording).
What changes
| Rule | California | Virginia | Oregon |
|---|---|---|---|
| Parking near a fire hydrant | 15 feet | 15 feet | 10 feet |
| Unposted limit, other roads | 65 mph on most highways | 55 MPH | 55 mph |
| School zone speed | 25 mph | 25 MPH | 20 mph |
| Under-21 alcohol limit | 0.01% | .02 | See the manual |
| Dim lights when following | Not captured | Within 200 feet | Within 350 feet |
Rules found in one handbook and not the others
- California paints curbs in colours with different parking meanings, and limits driving in a center left turn lane to 200 feet.
- Virginia allows a left turn on red from a one-way street onto another one-way street.
- Oregon forbids U-turns between intersections in a city and at intersections controlled by a signal unless a sign permits.
A rule appearing in one handbook does not mean the other states lack it; it may simply be worded elsewhere. That is the point: only your own state's handbook tells you its rule.
If you move
New residents normally have to get a license from the new state within a period set by that state, and may have to pass its knowledge test. Read the new state's handbook even if you have driven for years; the numbers you remember may be the old state's.
If you are visiting
You drive under the rules of the state you are in. Before a road trip, look up that state's rules on right turns on red, phone use and speed limits.
Next
How the knowledge test works Practice test
Independent practice site. DMV Practice is not a government website and is not connected with any Department of Motor Vehicles or licensing agency. The questions are our own, written from each state's public driver handbook as we read it on 12 November 2026. They are not the official test questions. Laws change: the current handbook of your own state is the authority.