According to the regulation DOT (Department of Transportation) requires the trailer lights to be visible at night and in various other low-light conditions. Well, this will improve road visibility and will protect the driver from dangerous collisions or accidents at night. It is mandated by the DOT that trailer light regulations require that a trailer must have two red brake lights. It must also have the reflectors present on each side at the rear. 

They must also light up when the brakes are pressed. Also, with these requirements, other lighting regulations must be maintained according to the trailer DOT inspection.   

What are the requirements for side lighting?

Sidelights are essential to ensure other drivers are aware of a trailer’s size and presence. These lights must be placed on each trailer side in the same spot. They should be positioned as close to the back as possible and be red. The lights can be mounted between 15 and 60 inches high. The front side sidelights should be yellow and also placed as close to the rear as possible. They must be at least 15 inches off the ground.

For trailers longer than 30 feet, intermediate sidelights are necessary to indicate the trailer’s length. These yellow lights should be placed in the middle of each side of the trailer, at least 15 inches high.

Requirements for rear lighting

Trailers in the United States need the following rear lights:

• License Plate Light: A single white light to illuminate the license plate.
• Turn Signals: A pair of red or yellow lights to indicate turns.
• Taillights: A pair of red lights to show the trailer’s width.
• Brake Lights: A pair of red lights to signal when the brakes are applied.

According to the NHTSA, except for the license plate light (which must be mounted next to or above the plate), all other lights should be between 15 and 72 inches high. They must be placed symmetrically and as far apart as possible to ensure maximum visibility and trailer safety.

What about the trailers that are extra wide?

To indicate the proper width of the trailer, there is a need for additional lighting in the front and rear and it must be more than 18 inches wide. Well, at the widest point of the trailer, two red clearance lights must be placed. Also, there must be three red identification lights that must be at the trailer’s center rear and the widest point on the trailer. It must also be adjusted at the highest point and must be at a distance of 6 to 12 inches from each other. 

But wait, there’s more!

The lights mentioned above need to be permanently attached to the trailer.

Here are some additional guidelines that don’t apply to photometrically installed lights for those placed at the certified angle:

• Front and back lights should be positioned perpendicular to the trailer’s centerline.
• Side trailer lights should be parallel to the trailer’s centerline.

Also to make the trailer more visible and indicate its size, the NHTSA requires that side and rear reflectors be part of the trailer’s equipment.

Trailer Light Regulations According To The DOT

Let us explain the following trailer light regulations:

Visibility requirements

Well, trailers are just like the other vehicles on the road. They must have an operable and visible lighting system from a distance of 500 feet. Well, this includes the two red stop lamps in the back, amber side marker lights, two white license plate lamps, two tail lamps in the rear, a clearance lamp for each side, reflectors on each corner, and two amber turn signals. 

All the lights must be placed and designed so that their visibility is not blocked by any other trailer component for example by a cargo bed. 

Rear lights and reflectors

Rear lights are crucial for identifying the width and length of your trailer in the dark or during foggy weather. Every trailer needs a red tail light on both the rear left and right sides. These lights must be visible from at least 500 feet away. Having properly functioning rear lights ensures that other drivers can see your trailer. It helps to prevent accidents. Whether you’re driving at night or through thick fog, these lights play a key role in keeping you and others safe on the road. Make sure they’re always in good working order.

Clearance lights

These lights must be placed at the rear side of the trailer. These lights are typically amber or red. The clearance lights must be visible from a distance of 500 feet and must be mounted between 12 to 60 inches off the ground. 

Reflectors and side marker lights

Having side marker lights is essential and ensures safety. It must be present on all the trailers that are over 80 inches in wish. 

These lights must be amber in color and should be visible from a distance of 500 feet. The reflectors can be either red or white. They must be installed around the side and the rear of the trailer which can increase your trailer’s visibility. All the reflectors must be visible from the side of the trailer from a distance of 50 to 500 feet. 

Tail, Combination Stop, and Turn Signal Lamps

The combination of the tail, combination stop, and turn signal lamps must be placed 15 to 72 inches from the ground. The visibility of the lights must be from 500 feet in normal daylight conditions. The amber turn signal lamps should be able to flash at the rate of 60 to 120 times per minute. 

Extra Wide trailers

Two extra turn signal lamps and stop lamps must be placed on each side of the extra wide trailers. The distance between the center of these lamps should be at most three feet apart. These lights must also be adjusted according to the height requirement which is 15 to 72 inches from the ground. 

Technomech Trailer Repair: Trailer repair in Houston

At Technomech Trailer Repair, we can handle trailer repair and more. Safety must be of utmost priority when you are towing a trailer. You must ensure that you follow all the federal regulations that are set by the Department of Transportation for every vehicle and trailer on US roads. 

Now that you are aware of all the light requirements on every kind of trailer, you must ensure that you are lights are mounted at the right place. 
Get in touch with us for more information about the trailer lighting requirements. We can get you going with the trailer lighting and every trailer checklist.