Truck Mirror and Seat Adjustment

Professional drivers know that the placement of mirrors and seats can have a huge impact on safety. Correct mirror placement is essential to have full visibility, while good seat placement can help prevent fatigue. Drivers should ensure that they are setting these properly during the pre-trip inspection.

Always position the seat before moving mirrors, so they are adjusted for maximum visibility from the correct seat position.  Seat placement should ensure enough leg room, allowing the knees to be slightly bent without having to stretch to reach the pedals. A proper seat tilt is also important for driving posture. Drivers should make sure their thighs extend beyond the front of the seat if possible, so that the back of their knees do not make contact with the seat.

Proper seat height and angle also ensure the driver is seated in the correct spot. Raise the seat to allow a good view out of the windshield, but not so high that the driver’s legs will interfere with the steering wheel. When it comes to angle, the chair should support the upper body while maintaining an upright and attentive posture. The best way for drivers to do so is to recline the seat so that the shoulders are no longer in line with the hips but are solidly behind them.​

When it comes to mirrors, there are several things to remember. Side-mounted flat mirrors should be positioned with the inside edge aligned with the vehicle body and placed at eye level. These mirrors are essential to capture the left and right edges of the truck, as well as to see traffic in adjacent lanes.

Convex mirrors should be mounted on the side in a position to avoid interference with flat mirrors. If properly adjusted, when a vehicle disappears from the flat mirror, it should appear in the convex mirror. The best convex mirrors have a radius of curvature between 20-30 inches for the most effective coverage. This can create a distorted perception of distance but ultimately offer a wider field of view.

Fender-mounted convex mirrors should be installed as far forward as possible. These further reduce blind spots, especially on the right side of the truck where visibility is most limited. Fender-mounted mirrors in the front are important for detecting pedestrians and small vehicles.

Start aligning flat mirrors first and then move to side convex mirrors. Adjust the fender mirrors last. When they are properly adjusted, the views from the mirrors should overlap with each other to ensure minimal or possibly no blind spots.

The most effective way to check for proper mirror adjustment is having a mirror check station.  A mirror check station requires quite a bit of open space. Use these instructions, along with the following graphic, to set up a station:

1. Position the truck as close to parallel to Line A as possible.
2. Stop with the side flat mirror over Line B.
3. Rotate each flat mirror horizontally until the inside edge only shows the left and right edges of the trailer.
4. Tilt each flat mirror vertically until the Target C on the appropriate side is in the bottom of the mirror.
5. Repeat step 3 with the side-mounted convex mirrors.
6. Tilt each convex mirror horizontally until Target C is visible in the top of the mirror.
7. Adjust the fender mirrors so that the inside edge shows the side of the trailer.

Don’t have the proper space for a mirror check station?  Another way to check mirror alignment is with markings on the truck and trailer. Mirror adjustment marks also allow for easy movement of the mirrors on the road if it becomes necessary.