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Is It Illegal to Stay in the Left Lane? Unveiling the Truth Behind Left Lane Laws

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Stay in the Left Lane

Is it illegal to stay in the left lane? Large trailers and trucks are bound by law to stay in the right lane. This applies to many States in the US, and Missouri is no exception. The Missouri laws were approved in 2018 regarding the circumstances in which the trailers and trucks are allowed by law to stay in the right lane. The left lane laws apply to larger-sized vehicles, but some medium-sized vehicles also have to follow these rules.

In this article, we will discuss the driving in left lane laws, the implications of left lane driving laws, and what happens if the left lane driving law – especially Kansas left lane law is violated. Discover Missouri’s left lane driving laws, including regulations for left lane trucking. Stay informed and navigate safely with our expert guidance.

Do Missouri Laws Permit Semi-Trucks to Drive in the Left Lane?

In Missouri, semi-trucks aren’t allowed to drive in the left lane of the roadways, highways, or the roads in civic areas. The law of driving in the left lane applies to the:

  • Vehicles that weigh above 48,000 pounds
  • Vehicles that are able to carry over 8 passengers, and
  • Weight vehicles

Truckers might choose the left lane to prevent disturbances from on-ramp merging traffic. However, semi-trucks constantly travel slower than other vehicles on the trace, so if they remain in the left lane when it is not necessary to do so could impact another motorist’s capability to drive safely. This is because vehicles in the left lane which are driving slowly, may beget other vehicles to weave in and out of other lanes, which could lead to a truck accident.

Which Vehicles are Banned from Left Lane Driving?

In the state of Missouri, the law of driving in the left lane applies to large vehicles such as trucks, trailers, and other large vehicles specifically vehicles weighing above 48,000 pounds, used for property transportation, and vehicles that are used to carry goods or merchandise and the ones which carry above 8 passengers. However, the shuttle buses or the vanpools are excluded.

Where are These Laws in Force?

The laws of left lane driving are not applied in the areas where only a single lane is present heading towards each direction. The laws of left-lane driving are not applied in the areas where only a single lane is present heading towards each direction. Moreover, the left-lane driving law also does not apply to highways where only two driving lanes are present on the highways. These laws are only applicable on the highways in urban areas where three driving lanes are present. 

Do these Laws Permit any Exceptions? 

The main exception that is permitted according to this law is the use of an entrance or exit on the left side of the highway. Otherwise, it is illegal to drive in the left driving lane. According to the left lane law, trucks or heavy vehicles are allowed to use the left lane for a very limited span when it is safe to do so and to enter or exit the highway or to shift from one lane to the other safely. 

Why are Left Lane Laws Necessary? Dangers Posed by Trucks in the Left Lane 

The left lane laws are important for several reasons.

  1. The flow of traffic: If the slow vehicles occupy the left lanes, it will cause the traffic to slow down and can result in traffic congestion or traffic jams. Allowing fast-moving vehicles to travel in the left lane facilitates a smooth flow of traffic.
  2. Reducing Road Rage: These laws help in avoiding negative behaviors on the road i.e. frustration can build up among the drivers if the left lane is blocked by slow vehicles. 
  3. Enhancing safety: Keeping the left lane vacant for passing can help in reducing the rate of lane changing, which is the main source of road accidents. 
  4. Predictable patterns: When drivers follow a pattern of driving in the right lane unless there is a need to pass, it helps to predict the behavior of other drivers, which helps in reducing the number of unfortunate road fatalities and injuries.
  5. Emergency vehicle access: The unoccupied left lane contributes to providing easy access for the emergency service providers such as ambulances or police. It helps them to avoid the traffic on the road and pass quickly in cases of emergencies. 

Legal Consequences for Missouri’s Left-Lane Driving

The legal consequences of violating Missouri left lane law can result in:

  • Fines.
  • Reduction of points on the driver’s records.
  • License suspension in cases of a gross violation resulting in a fatal accident.

How to Safely Navigate Around Trucks in the Left Lane

Using an appropriate way to navigate around the trucks in the left lane is necessary to avoid accidents or mishaps on the roads. Following are some of the ways drivers should implement while navigating around the trucks or heavy vehicles in the left lane

  • Use the indicator to inform that you are about to change the lane.
  • Check the mirrors and the blind spots to make sure that there is enough space to merge in the lane.
  • Increasing the distance between your vehicle before changing lanes helps in safe lane changes.
  • Increase the speed gradually while changing the lane.
  • Maintain a constant speed while passing the truck and avoid any sudden locomotion.
  • Drive at a safe distance from the blind spots of the truck, especially the right side.
  • Avoid cutting too closely in front of the truck. Make sure to give them ample space.


In a nutshell, the left-lane driving laws play an integral role in ensuring the safe and efficient flow of traffic in Missouri. These laws are enforced to prevent large vehicles from unnecessarily occupying the left lane. The no trucks left lane law facilitates a smoother flow of traffic, reduces congestion on the roads, prevents road rage incidents, and increases the overall safety of the roads. 

If you have suffered an accident due to a driver’s negligence in observing left-lane laws,

consult our expert truck accident lawyers at Royce Injury to understand your options.

Jason Royce Allen

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