Do I need an International Driving Permit to drive in the US?

US law is set state by state, but as a visitor you can generally drive on your valid foreign license for a limited period. Many states also want an International Driving Permit (IDP) — a certified translation of your license — and rental companies and police often expect one if your license isn't in English. It doesn't replace your license; carry both.

What is the speed limit in the US?

There is no single national limit — each state sets its own, posted in miles per hour. Rural interstate limits run from about 65 to 80 mph, with Texas topping out at 85 mph on one stretch and Washington, DC as low as 55 mph. Always follow the posted sign; it overrides any general figure.

Is right turn on red allowed everywhere in the US?

Almost. In every state you may turn right at a red light after coming to a full stop and yielding, unless a sign says otherwise. The big exception is New York City, where right turn on red is prohibited unless a sign specifically allows it. Watch for 'No Turn on Red' signs anywhere.

What is the drink-driving limit in the US?

It's illegal to drive with a blood-alcohol concentration (BAC) of 0.08% or higher in every state except Utah, where the limit is 0.05%. Drivers under 21 face near-zero-tolerance limits everywhere, and commercial drivers are held to 0.04%.

Driving in the USA: US traffic rules explained

Driving in the United States is refreshingly straightforward, but the details catch people out — because there is no single national rulebook. The federal government sets a baseline, and then each state writes its own traffic code. Speed limits, phone rules, seat-belt enforcement and more all shift the moment you cross a state line. This is the plain-English memo: the rules that hold everywhere, the ones that vary, and where to check the official source for the state you're actually in.

Every US state page on RoadRange carries a "Traffic rules" panel with that state's top speed limit, seat-belt enforcement, phone rule and drink-driving limit, linked to the state's own handbook.

Start with the basics

Drive on the right, and pass on the left. On multi-lane highways you may legally pass on the right, but the left lane is for overtaking — don't camp in it.
Everything is in miles. Distances are in miles and speeds in miles per hour (mph). One mile is about 1.6 km; 60 mph is roughly 97 km/h.
Bring the right license. US drivers use their state license. Visitors can usually drive on a valid foreign license for a limited stay; many states and most rental firms also expect an International Driving Permit if your license isn't in English. See the U.S. government's overview for visitors at usa.gov.
Carry proof of insurance and registration. Nearly every state requires liability insurance, and you must be able to show it (and the car's registration) if you're stopped.

Speed limits vary by state

Limits are always posted in mph, and the sign is the law — there's no default you can fall back on. Rural interstate maximums range from about 65 mph up to 80 mph across the Mountain West, with Texas posting the country's highest limit at 85 mph on one tolled stretch and Washington, DC among the lowest at 55 mph. Speeding is one of the largest factors in US road deaths, and enforcement (including automated cameras in some states) is common. See NHTSA on speeding and the IIHS speed-limit tables for the state detail.

Seat belts and child seats

Buckling up is required for front-seat occupants in every state except New Hampshire (which still mandates belts for anyone under 18). Where states differ is enforcement: under primary enforcement an officer can pull you over for the belt alone; under secondary enforcement they can only add the ticket to another stop. Child-restraint rules — car seats and boosters by age, height and weight — vary by state, so check locally before you travel with kids. See NHTSA on seat belts and NHTSA car seats & booster seats.

Drink-driving (DUI / DWI)

Driving under the influence is treated seriously everywhere. The illegal limit is a blood-alcohol concentration of 0.08% in every state except Utah, which sets it at 0.05% — the strictest in the nation. Drivers under 21 face zero-tolerance laws (typically 0.01–0.02%), and commercial drivers are capped at 0.04%. Penalties escalate quickly and can include losing your license. See NHTSA on drunk driving.

Phones and distracted driving

Texting while driving is banned for all drivers in nearly every state. Beyond that, states split into two camps: hands-free states ban holding a phone at all, while others prohibit texting but still allow hand-held calls. The list of hands-free states keeps growing, so treat "hands-free everywhere" as the safe default. See NHTSA on distracted driving and the GHSA distracted-driving law tables.

Right turn on red

In all 50 states and DC you may turn right at a red light after a full stop, once you've yielded to pedestrians and cross traffic — unless a sign prohibits it. The major exception is New York City, where right turn on red is not allowed unless a sign says you may. Watch everywhere for "No Turn on Red" signs, common at busy intersections. The rules for signals and signs are standardized nationally by the Federal Highway Administration's Manual on Uniform Traffic Control Devices (MUTCD).

Stop signs, four-way stops and roundabouts

Four-way (all-way) stops trip up visitors: everyone stops, and you proceed in the order you arrived. If two of you stop at the same time, the driver on the right goes first.
Roundabouts are spreading. Yield to traffic already in the circle, enter when there's a gap, and signal as you exit.

School buses — stop when the red lights flash

A stopped school bus with flashing red lights and an extended stop arm means traffic must stop in both directions while children board or get off. The only common exception is oncoming traffic on the far side of a divided highway with a median. This is taken very seriously and heavily fined. See NHTSA on school-bus safety.

Move over for stopped emergency vehicles

All 50 states have a "Move Over" law: when you approach a stopped emergency vehicle, tow truck or other vehicle with flashing lights on the shoulder, you must move over a lane if you safely can, or slow down significantly if you can't.

Toll roads, HOV lanes and turnpikes

Many highways charge tolls, and a growing number are cashless — they read a transponder or photograph your plate and bill you (or the rental company) later. Ask your rental firm how tolls are handled. HOV / carpool lanes are reserved for vehicles carrying a posted minimum number of people; using one alone can bring a hefty fine.

If the police stop you

Pull over to the right as soon as it's safe and stay in the car unless asked to step out. Keep your hands visible (on the wheel), and have your license, registration and proof of insurance ready — tell the officer before reaching for anything in the glovebox. Being calm and cooperative goes a long way.

How this fits your road trip

Knowing the rules is half of arriving relaxed; knowing how far you can realistically get is the other half. Pick your starting state on the US states map to see its traffic-rules panel alongside its parks and driving notes, or read how far you can actually drive in a day before you plan the route.

Official sources

The rules above are summarized from official and authoritative sources. Always confirm the specifics for the state you're driving in — each RoadRange state page links to that state's own driver handbook.

Speeding — NHTSA; state limits via the IIHS.
Seat belts & child seats — NHTSA seat belts, NHTSA car seats.
Drunk driving — NHTSA.
Distracted driving & phones — NHTSA, GHSA.
Signs, signals & right turn on red — Federal Highway Administration MUTCD.
School-bus safety — NHTSA.
Driving in the US as a visitor — usa.gov.

NHTSA, the FHWA and usa.gov are U.S. government sources; the IIHS and GHSA are independent road-safety organizations whose state-law tables cite the underlying statutes.

Frequently asked questions

Do I need an International Driving Permit to drive in the US?: US law is set state by state, but as a visitor you can generally drive on your valid foreign license for a limited period. Many states also want an International Driving Permit (IDP) — a certified translation of your license — and rental companies and police often expect one if your license isn't in English. It doesn't replace your license; carry both.
What is the speed limit in the US?: There is no single national limit — each state sets its own, posted in miles per hour. Rural interstate limits run from about 65 to 80 mph, with Texas topping out at 85 mph on one stretch and Washington, DC as low as 55 mph. Always follow the posted sign; it overrides any general figure.
Is right turn on red allowed everywhere in the US?: Almost. In every state you may turn right at a red light after coming to a full stop and yielding, unless a sign says otherwise. The big exception is New York City, where right turn on red is prohibited unless a sign specifically allows it. Watch for 'No Turn on Red' signs anywhere.
What is the drink-driving limit in the US?: It's illegal to drive with a blood-alcohol concentration (BAC) of 0.08% or higher in every state except Utah, where the limit is 0.05%. Drivers under 21 face near-zero-tolerance limits everywhere, and commercial drivers are held to 0.04%.