Keep-right lane laws require you to drive in the right-hand lane on a multi-lane road whenever you’re moving slower than the surrounding traffic, and to use the left lane only for passing, left turns, or a short list of other specific reasons. The threshold is the speed of the cars around you, not the number on the speed limit sign. You can be going exactly the posted limit and still be legally required to move right if traffic around you is moving faster.
The Default Rule
The Uniform Vehicle Code, which most state traffic codes are modeled on, puts it this way: any vehicle traveling slower than the normal speed of traffic must drive in the right lane or as close to the right edge of the road as practical. The operative language is “normal speed of traffic at the time and place and under the conditions then existing.”1The Center for Constitutional Excellence. Uniform Vehicle Code Your obligation is pegged to what other drivers are actually doing.
Two exceptions are baked into the baseline rule. You don’t need to stay right when you’re overtaking another vehicle going the same direction, and you don’t need to stay right when you’re preparing for a left turn at an intersection or into a driveway.1The Center for Constitutional Excellence. Uniform Vehicle Code
In practical terms, the right lane is your default. You move left to pass, then get back over. Treating the left lane as a personal cruising lane because your speed feels fast enough violates the rule in most states, even when you’re at the posted limit.
When You’re Allowed to Leave the Right Lane
Beyond passing, several situations justify being out of the right lane. These exceptions appear in virtually every state’s version of the law:
- Preparing for a left turn at an intersection or a left-side highway exit, which you need to position for in advance.
- Avoiding obstructions in the right lane, including debris, disabled vehicles, construction zones, or any physical hazard.
- Making room for merging traffic entering from an on-ramp.
- Following traffic control devices. Lane-use signs, detour markings, and construction-zone signage override the default right-lane rule.
Roadway markings matter too. Broken white lines between lanes mean lane changes are permitted; solid white lines mean lane changes are discouraged or prohibited. Whichever exception applies, signal before you move.
How Strict Your State Is
States didn’t all adopt the model language the same way. A handful restrict the left lane strictly to passing and left turns, making it illegal to cruise there for any other reason. Some states only require you to move right when you’re actively blocking faster traffic behind you. The largest group follows the model and requires you to keep right whenever you’re traveling slower than the flow around you. A small minority have no meaningful keep-right requirement, or let you stay left as long as you’re at the speed limit.
If you drive across state lines, assume the strict version. That assumption keeps you legal almost everywhere. The strictest states don’t care whether you’re at the limit or slightly above it: if you’re in the left lane and not passing anyone, you’re in violation.
Passing the Right Way
Passing isn’t just moving into the left lane and staying there. The model code treats it as a sequence. You pass to the left of the slower vehicle at a safe distance, and you don’t return to the right lane until you’re safely clear of the vehicle you passed.2I Am Traffic. Millennium Edition of the Uniform Vehicle Code – Section 11-303
The driver being passed has an obligation too. If someone is overtaking you, you’re required to give way to the right and not speed up until the passing vehicle has gone by. Speeding up to block a pass violates the model code in most states.2I Am Traffic. Millennium Edition of the Uniform Vehicle Code – Section 11-303
Signal, check your blind spots, complete the pass with enough speed that you aren’t lingering alongside the other vehicle, and merge back once you can see them in your rearview mirror. The goal is to spend as little time in the passing lane as possible.
When Passing on the Right Is Legal
Passing on the right has a reputation as always illegal, and that reputation is wrong. Under the model rule, you can pass on the right in two situations: when the vehicle ahead is making or about to make a left turn, or when you’re on a road with at least two lanes of unobstructed pavement going your direction.3I Am Traffic. Millennium Edition of the Uniform Vehicle Code – Section 11-304
The hard limit: you can never pass on the right by driving off the roadway. Using the shoulder, berm, or an unpaved area to get around someone is illegal in every situation. The maneuver also has to be safe under the conditions at the time. Having the legal right to pass on the right doesn’t mean you should do it in heavy traffic or poor visibility.3I Am Traffic. Millennium Edition of the Uniform Vehicle Code – Section 11-304
So when someone sits in the left lane on a four-lane interstate and you go around them in the right lane, you’re not breaking the law. The left-lane camper probably is.
Rules for Trucks, RVs, and Trailers
Separately from keep-right rules, many states prohibit heavy commercial vehicles from using the far-left lane on multi-lane highways. No single federal regulation requires this. Each state sets its own rules, and local governments can impose restrictions on individual roadways even when the state has no blanket law.4Federal Highway Administration. Freeway Management and Operations Handbook – Chapter 8
The weight thresholds and vehicle definitions vary. Some states set the cutoff at 10,000 pounds gross vehicle weight. Others target vehicles with more than two axles or more than six wheels. A few use much higher thresholds in the range of 26,000 or even 48,000 pounds. At least three travel lanes in your direction are typically needed before these restrictions apply.4Federal Highway Administration. Freeway Management and Operations Handbook – Chapter 8
If you drive a truck, RV, or anything towing a trailer, watch the signs. “No Trucks Left Lane” is enforceable regardless of whether you think you’re going fast enough to belong there.
Move-Over Laws Pull You Out of the Right Lane
Every state and Washington, D.C. requires you to move over or slow down when you approach a stopped emergency vehicle with its lights flashing. When you see a police car, fire engine, ambulance, or similar vehicle on the shoulder, you must change into a lane that isn’t directly next to it. If traffic makes a lane change unsafe, you’re required to slow down significantly.5National Highway Traffic Safety Administration. Move Over – Its the Law
Nineteen states and D.C. now extend the same requirement to any vehicle with flashing or hazard lights, including tow trucks, highway maintenance crews, construction vehicles, utility trucks, and disabled civilian vehicles.5National Highway Traffic Safety Administration. Move Over – Its the Law More than half of all states have broader protections of some form, and that number continues to grow.6Traffic Safety Marketing. Move Over Safety The habit worth building is to move over for any stopped vehicle on the roadside, not just the ones with official markings.
What a Violation Costs
Fines for keep-right and lane discipline violations vary. Some states set them under $50; others reach $200 or more. The direct fine is usually the smaller part of the cost. Most states also assess points against your driving record, commonly two to three points per conviction, and enough points within a set period can trigger license suspension. Reaching four to eight points within one to three years is a common danger zone.
Insurance is the longer tail. A single moving violation can raise premiums by roughly 20 to 30 percent, and the surcharge tends to follow you for three to five years. A $150 ticket can translate into several times that amount over the life of the increase.
Move-Over Penalties Are Different
Move-over violations are treated far more seriously. Fines run from $30 to $2,500 depending on the state, and at least 21 states have added criminal penalties for violations that cause damage or injury to a protected vehicle or responder. In some states, causing bodily injury to an emergency worker by failing to move over is a felony, and causing a death elevates the charge further.5National Highway Traffic Safety Administration. Move Over – Its the Law Jail time is on the table in the most serious cases.