Semi-Truck Blind Spots: A Comprehensive Overview

Most of us have experienced that moment when another driver merges in front of us, cuts us off, or simply acts as if we aren’t there. More than likely, you are in one of the driver’s blind spots: a place where the design of their vehicle obscures their view. All large commercial trucks and buses have blind spots — and the stakes get higher as the vehicle gets larger.

Injured in a truck accident? Call the Poole Law Group: 301-790-3600

Consider 18-wheelers. Also called “semi-trailer trucks” or “tractor trailers”, 18-wheelers are large trucks consisting of a tractor (engine) unit and freight-carrying trailer unit (also known as “tractor-trailers”). The driver’s view is about 9-10 feet from the ground, so they can see over the engine.

Due to the size of the vehicle and the position of the driver, semi-truck blind spots are much larger — and more dangerous — than the blind spots in a passenger vehicle. While we would hope truck drivers would show proportionate caution, many do not; thousands of tragic truck accidents happen on our roads every year because truck drivers fail to check their blind spots.

There are four main blind spots on a semi-truck:

Directly in front of the truck. Drivers are unable to see approximately 20 feet in front of the truck; if a vehicle in front of them stops suddenly, they may not be able to stop in time. This is why truck drivers have a responsibility to keep a considerable distance in front of them.

Directly behind the truck. While many trucks are now equipped with rear-view cameras, some truck drivers cannot see what is directly behind their trucks and must anticipate drivers in changing road conditions.

A widening angle from the driver’s side door. The truck driver has a blind spot on the left side of the truck, extending directly behind the 18-wheeler at about a 30-degree angle. They must be vigilant to check when merging or turning left.

A widening angle from the passenger’s side door. The truck driver’s blind spot on the passenger side extends from the front of the vehicle, at about 4-6 feet behind the cab, to an area directly behind the 18-wheeler at about a 30-degree angle. Many truck drivers will fail to check this angle and catch smaller vehicles in an infamous “right hook” when turning right.

Source: Maryland Motor Vehicle Administration

Because tractor-trailers sit so high up, vehicles that are right next to the truck are essentially invisible to the driver. Side-view mirrors do not allow for visibility directly in front of, below, or behind the rig. Truck drivers have a responsibility to look out for their fellow motorists. While most are law-abiding, some truck drivers take undue risks and put other drivers in danger.

As a truck driver, what can I do to avoid auto accidents due to my blind spots?

Maintain a safe speed and lane presence.

Signal lane changes and gives extra time for motorists to respond.

Always double-check your blind spots, particularly on the passenger side; remember, you are responsible for making sure your blind spots are clear before merging.

Never follow too closely behind another vehicle; in trucking accidents, rear-end collisions can easily be fatal.

Never text and drive; avoid driving when texting is necessary.

Always allow for enough rest and recovery. Make sure your trucking company requires and enforces the minimum required rest periods between your shifts.

Truck Blind Spots: Frequently Asked Questions:

Where is the largest blind spot when near a large truck?

The largest blind spot near a large truck is on the right side, extending several lanes. This blind spot can stretch for significant distances, sometimes up to 30 feet or more. Trucks have limited visibility on the right due to the height and length of the vehicle. Commercial truck driving classes focus on checking rear-view mirrors before pulling out or merging into other lanes of traffic.

How big are the blind spots in a semi-truck?

The blind spots around a semi-truck, also known as "no-zones", vary in size depending on the truck's length and height. General estimates are as follows:

Front: Semi-trucks have a blind spot extending roughly 20 feet in front of the truck. Smaller vehicles driving too close to the front of the truck are often invisible to the driver.
Right side: This is the largest blind spot, extending across several lanes. It can stretch as far as two lanes wide and approximately 30 feet behind the truck.
Left side: The left side has a smaller blind spot, typically extending from the rear of the trailer and running about half the length of the truck. Drivers should still avoid lingering in this area.
Rear: Directly behind the trailer, this blind spot can extend as far as 200 feet.

Do big trucks have bigger blind spots?

As a general rule, yes: the larger the vehicle, the larger the blind spots. Moreover, the size and shape of a semi-truck can create large blind spots on all four sides of the truck.

How does truck size affect blind spots? Trucks sitting higher off the ground must be extra careful to see and accommodate smaller vehicles directly in front of, behind, or alongside the truck. Similarly, a semi-truck with a trailer can be up to 80 feet long; this extended length creates long blind spots, particularly on the sides and rear. Finally, trucks with larger turning radiuses have larger blind spots on their right side.

The larger blind spots mean truck drivers have to rely heavily on their side mirrors, but even those can't cover all areas. Truck drivers must exercise extreme caution as smaller vehicles may be hidden from sight in these zones.

How many blind spots does a truck have?

A truck has four (4) major blind spots:

in front (about 20 feet directly in front of the truck's cab);
on the right side (extending up to two lanes wide and stretching along most of the truck’s length);
on the left side (a narrower gap but critical to note when merging left) and
at the rear of the truck (extending up to 200 feet).

Which side of a semi-truck has the biggest blind spot?

The right side of a semi-truck has the biggest blind spot. This blind spot can extend across two lanes and runs the length of the truck, making it especially dangerous for smaller vehicles driving alongside. Truck drivers have limited visibility on the right side due to the position of their mirrors and the truck's length, which means they must exercise extreme caution when turning and merging right.

How are truck drivers trained to manage their blind spots?

Given the tremendous risk that dangerous driving poses, truck drivers are trained to be aware of the locations of their blind spots. They are taught to use several strategies and tools to minimize the risks associated with them:

Side-View Mirrors: Trucks are equipped with large side mirrors, including convex mirrors that offer a wider field of view. Drivers must check them frequently, with the knowledge that most mirror configurations do not remove blind spots entirely.

Blind-Spot Monitoring Systems: Many modern trucks are equipped with blind-spot detection systems that use sensors to monitor the areas around the truck and alert drivers if a vehicle is present. In some trucks—especially newer models—rear-view cameras are installed to help eliminate the large blind spot behind the truck when backing up.

Lane-Change Etiquette: Truck drivers must signal early and check mirrors carefully before turning or changing lanes, as these actions increase the chances of hitting a vehicle in a blind spot. Some drivers perform a brief "lean and look" movement, adjusting their position in the cab to get a better angle on areas near the truck that may not be fully visible in the mirrors.

Defensive Driving: Truck drivers are trained to be extra cautious and practice defensive driving, assuming that vehicles may be in their blind spots. They maintain safe distances, signal turns well in advance, and often take extra time to merge or switch lanes to avoid blind spot accidents. In addition to checking their blind spots frequently, truck drivers should maintain a safe speed, an appropriate driving distance, and an active awareness of the surroundings at all times.

At the Poole Law Group, we want you to stay safe on the road. Truck accidents are more common than many people realize; because of their size, a truck is capable of generating between 16 to 20 times more force than a passenger vehicle, which is why it’s critically important for trucks to use extreme caution when sharing the road with smaller vehicles.

Have you been injured in a truck accident? Call the truck accident lawyers at the Poole Law Group for a free consultation: 301-790-3600.