Which Laws Regulate Car Driver Behavior? Ultimate Guide

The U.S. Department of Transportation (DOT) oversees all federal transportation policies and regulations. The laws listed in this guide are those I could find in my extensive research that regulate car driver behavior.

They cover most of what drivers should and shouldn’t do on the road. The main goal is to ensure safe traveling in public roads and increase national mobility. Drivers that behave well on the road significantly reduce their risk of being involved in an accident.

Laws that Regulate the Behavior of a Car driver

  • Speed limit laws
  • Right-of-way rule
  • Passing other vehicles (Overtaking)
  • Move Over Law
  • Impaired driving law
  • Distracted driving law
  • Laws for signaling and lighting

Which laws regulate car driver behavior?

1.    Speed Limit Laws

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The law sets a maximum speed limit of 70 mph (113 km/h) on interstate highways, 65 mph (105 km/h) on four-lane roads, 55 mph (89 km/h) on other two-lane roads, and 45 mph (72 km/h) on rural pave county roads.

These values are not necessarily the fastest or slowest you can go. They are a baseline for statutory speed limits. Many states have the mandate to adjust their limits, with some having lower limits for certain types of vehicles and certain types of roads.

There are sub-rules that exist under speed limit laws. They include:

a) Basic Speed Rule:

This rule requires car owners to drive at a speed that is prudent and reasonable. Every person shall drive at an appropriate and safe speed when:

  • Approaching and crossing an intersection or railroad grade crossing
  • Approaching a hill crest
  • Traveling upon any narrow or winding roadway
  • Approaching and going round a curve
  • Special hazards exist with respect to traffic or pedestrians due to highway or weather conditions

b) Minimum Speed Rule

This rule prevents people from driving a motor vehicle at such a slow speed as to impede the reasonable and normal movement of traffic. However, to avoid conflict, the law allows for slow speed when it’s necessary for safe operation or in compliance with the law.

How much over the speed limit can you go?

The law does not allow drivers to go over the speed limit. Anything above what is set can get you a speeding ticket. Fortunately, the police sometimes offer a 10% plus 2 mph buffer above the limit. This is of course, at their discretion.

What is the highest legal speed limit in the world?

As of 2018, the UAE had two motorways with a speed limit of 99 mph (160 km/h). This is the highest legal limit in the world. Germany is also known to have the world’s fastest roads. About 45% of the country’s autobahn network (roughly 3,590 out of 7,982 miles) has no speed limit.

Why are US speed limits so low?

Speed limits in the US were initially set low to reduce America’s gas consumption in the 70s. This was in light of President Nixon’s executive order to set a 55 mph speed limit on American highways.

This was based on an embargo set against the US by the Organization of Arab Petroleum Exporting Countries for supplying Israel with arms. Congress passed the president’s order into law and for 20 years, it became the baseline for low speed limits.

Today, speed limits are set low because it’s believed they make the roads much safer. The law sets a maximum speed limit of 70 mph and allows states to adjust limits in increments of 5 mph (8 km/h).

Texas boasts the highest speed limits in the country due to its wide open spaces. The law allows the Texas Transportation Commission to establish a maximum limit of 85 mph (137 km/h) if the highway can accommodate the speed.

2.    Right of Way Rule

The right of way rule provides guidelines on what every driver, motorcyclist, moped rider, and bicyclist must do to avoid a crash. It does not give anyone a right of way. It only states who must yield the right of way (give it up) and when.

Giving up the right of way to another vehicle means letting it go before you in traffic. The ‘Yield to the Driver on the Right’ rule controls most intersections when drivers arrive simultaneously.

For example, if two drivers arrive at a stop sign at the same, you yield the right of way to the other driver if they are on your right. If you arrive at an uncontrolled intersection at different times, the last driver to arrive must yield the right of way.

Bicycles are considered vehicles and are subject to the same rule. Car drivers must always yield the right of way to pedestrians at crosswalks and intersections. Failure to follow these rules can lead to a crash.

In summary, here are the instances where the right of way must be yielded to other drivers.

  • At a yield sign
  • At an uncontrolled intersection that already has vehicles
  • To pedestrians at crosswalks
  • To persons using a seeing eye guide dog or a white cane with or without a red tip
  • At a ‘T’ intersection where you must give up right of way on the through road
  • When getting your car into the roadway from a parked position
  • When driving on an unpaved road that intersects with a paved road
  • Turning left where there are oncoming cars, pedestrians, etc.

3.    Passing Other Vehicles (Overtaking)

The law requires drivers to pass other vehicles (overtake) using the left lane. A vehicle passing another that is moving in the same direction should pass to the left at a safe distance.

They should never use the right lane unless when it is safe to do so or completely necessary to avoid a traffic hazard. A vehicle operator should not return to the right until they are safely clear of the vehicle they just passed.

You should not:

  • Overtake another vehicle by driving off the main part of the road or using the pavement
  • Drive faster than the flow of traffic or over the speed limit
  • Pass where the center line is a double solid yellow line
  • Overtake where there is ‘DO NOT PASS’ sign
  • Pass when you do not have enough time to safely go back to your lane before meeting oncoming traffic or before reaching a solid yellow line
  • Overtake near a corner or the top of a hill where your view of oncoming traffic is blocked
  • Overtake when you’re less than 100 feet from a railroad crossing or bridge
  • Pass when you’re behind a school bus that’s loading or unloading children

4.    Mover Over Law

One of the many laws that regulate car driver behavior is the Mover Over Law (ORS 811.147). It dictates that drivers must give the right of way to emergency vehicles that have their emergency lights and siren on. If you are driving behind a police vehicle or any emergency vehicle, you must:

  • Move over to another lane
  • Slow down if you can’t safely change lanes
  • Provide as much room as possible for the emergency vehicle to pass

Emergency vehicle drivers typically overtake on the left whenever possible when responding to an emergency. Vehicle owners are required to slow down and pull over to the right and stop when it’s safe to do so.

If you have nowhere to pull over to or your vehicle is already stopped, the law requires that you stay put and allow the emergency vehicle to go around you. If you’re blocking the way, drive ahead and pull over into a clear area if you’re able to. Use your turn signal to indicate your intentions.

You’re also required to pull over and stop if an emergency vehicle is approaching from the opposite direction. You should not stop in the middle of the road or slam your bakes. You never know where the vehicle could be going to. Do not tailgate or follow it.

The Move Over Law helps to protect emergency workers and law enforcement officers from inattentive and speeding drivers. It also protects motorists from the emotional and physical dangers of a crash.

5.    Impaired Driving Laws

Impaired driving laws are also part of the regulations that regulate car driver behavior. They address alcohol-impaired driving and apply where drivers operate motor vehicles while under the influence of alcohol.

All states except Utah consider driving with a blood alcohol concentration (BAC) of or above 0.08% a crime.  

Each state has set specific laws and penalties. They include administrative license suspension (ALS) on the first offense, limited driving privileges, and an ignition interlock program that disables the engine of a convicted drunk driver if alcohol is detected in their breath.

6.    Distracted Driving Laws

The distracted driving law helps to prevent distraction caused by the use of a cell phone or similar electronic communication device while driving. In most states, it’s illegal for drivers to read, send texts or emails, and access the internet while the vehicle is in motion or is part of traffic.

A law enforcement officer has the right to stop any driver that is texting, reading, sending messages, or using any other portable electronic device. They can issue a warning or a fine. This is unless the car is at a complete stop and away from the traveled portion of the highway.

It’s also illegal to use your phone at a stop sign or stoplight. In most states, it’s also illegal to wear headphones, Airpods, or anything that’s covering, inserted in, or resting on the ears while driving.

However, in California and other states, you can use your mobile phone in a hands-free manner, such as voice commands or on speaker phone, but not while holding it. Drivers under the age of 18 are not allowed to use a cell phone for any reason.

There are other actions that are also considered a serious distraction. They include grooming, reading, reaching for objects, eating, talking to passengers, and changing clothes while driving. They can result in a “speed unsafe for conditions” or “reckless driving” ticket.

7.    Signaling and Lighting laws

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The different types of lights found on cars today include headlights, tail lights, daytime running lights, fog lights, signal lights, brake lights, hazard lights, and driving lamps.

Here, the laws that regulate car driver behavior are all over the place. The most important thing to know is what the lights do, how to use them, and when to use them.


Headlights allow drivers to see the road ahead in the dark. They also notify other motorists of a car’s presence. They are of two types – high beam and low beam.

High beam headlights provide an intense centered light that has no control of glare. They should only be used when there are no visible cars in front of you (going or coming).

Low beam headlights provide lateral and forward illumination without causing glare. They do not blind other road users and are best used when there’s no traffic in front of you.

The law requires drivers to have two functional headlights that can be used when it’s dark. Most states require them turned on:

  • 30 minutes after sunset to 30 minutes before sunrise
  • When visibility is low or,
  • In adverse weather conditions.

There is also a set limit for visibility (200-500 feet) in different states. Countries like Scandinavia require 24-hour headlight use, so be sure to confirm what headlight laws apply to the specific state or country you’re in.

Tail lights

Tail lights are the red lights that illuminate at the rear of your vehicle. They light up whenever the headlights are switched on. They notify the drivers behind you of your presence and tell them how far you are from them.

Daytime running lights

Daytime running lights (DRLs) are located below the main headlights both at the front and rear. They are not found in all vehicles. Their main job is to help other drivers to spot you in hazy or low visibility conditions.

Some people claim that they are an unnecessary feature. Depending on the vehicle you drive, you can turn off your daytime running lights. DRLs are a legal requirement in Canada and the UK, but not in the US.

Fog lights

Fog lights are located below the low beam headlights and are designed to shine down below the fog. This prevents light from refracting and glaring back at the driver. They are useful in foggy weather where normal headlights cannot see through.

Road rules concerning fog lights differ from state to state. So check to confirm what applies to your state.

In Florida, drivers are not allowed to use them and other auxiliary lights when cars are on the road except in foggy conditions. There’s a law in Oregon that prohibits their use when you are within 500 feet of oncoming traffic or within 350 feet if you are behind another car.

Read more: How to install fog lights on your car

Signal lights

Signal lights are also known as turn signals or blinkers. They are located both at the front and rear of the car next to the headlights and tail lights respectively. They help to indicate to other drivers which direction you’d like to make a turn.

Drivers are legally required to use turn signal lights when:

  • Making a right- or left-hand turn at an intersection
  • Parking on the side of the street
  • Changing lanes
  • Leaving a roundabout
  • Merging with traffic on a roadway
  • Overtaking or passing another vehicle
  • Pulling over to the roadside
  • Entering a parking lot or driveway on either side of the road

You’re required to use your turn signals even when no other vehicles or pedestrians are in the area. Turn them on approximately 100 feet before arriving at an intersection.

When indicating an exit on a highway, overtaking, or changing lanes; turn your signal lights on at least 900 feet before you make the turn.

You’re only allowed to use your hand to signal when your signal lights are not working or if other drivers can’t see your turn signals due to one reason or another.

Brake lights

Brake lights are red rear lights that are colored brighter than your standard tail lights. They turn on automatically when you step on the brake, signaling other drivers that you’re slowing down or coming to a stop.

Read more: How to Avoid Confusion Between The Brake and Gas Pedals

Hazard lights

Hazard lights are also referred to as flashers. They are located both at the front and rear of the car. They flash when turned on to notify other drivers that you’re in distress, potential danger, or there’s a road hazard ahead.

Use your hazard lights when:

  • You get into a car accident
  • You get pulled over by the police
  • Your car breaks down
  • You’re driving in a funeral procession
  • You’re changing a tire
  • You experience a mechanical problem while driving

You should not use your hazard lights when parking illegally, when stopping at a stop sign, or when driving in bad weather. Hazard lights laws differ from the state so be sure to check what is allowed in your state.

Reverse lights

Reversing lights are located at the rear of the vehicle. They are typically white in color and turn on automatically when you put the vehicle in reverse gear.

They signal to the vehicles behind you that you are about to reverse your vehicle.

Every car in the US is required to have one or two rear-facing reverse lights mounted at the rear. They must be white in color and are a standard requirement in all vehicles.

Driving lamps

Driving lamps are lights located inside the vehicle. They are used to brighten the interior to find items in the dark, check maps, or confirm directions. The state vehicle code does not address the use of interior lights.

In fact, it is perfectly legal in most states to drive with them turned on. However, it is generally considered unsafe as it reduces the sharpness of your night vision. It can make it harder to see the road and even distract other motorists.

On That Note

In summary, some of the laws that regulate car driver behavior are Speed limit laws, Right of way, Passing other vehicles (Overtaking), Move over law, Impaired driving law, Distracted driving law, and laws for signaling and lighting.

There are many state transportation laws not covered in this guide, including those regulating safety equipment requirements as well as private and commercial vehicle registration. You can check out LawInfo for other different areas where transportation law applies to.