How to Keep Trucks from Hitting or Becoming Stuck Under Overpasses

A problem exists, wherein operators of large trucks sometimes do not accurately measure the height of the vehicle or the extra height of the load that they are carrying. When they drive these trucks under a bridge or overpass that has a lower maximum height requirement, these trucks either strike the overpass or, in some cases, the vehicle becomes lodged beneath the overpass.

Instructions

Difficulty: Moderate

Things You’ll Need:

• Infrared photoelectric sensors
• Metal posts
• Signage
• Flashing lights

1. Excessive traffic congestion and the financial burden of removing lodged trucks and repairing overpasses is a good incentive to apply a relatively simple and inexpensive means of warning drivers if the load that they carry exceeds the maximum height for a bridge or overpass.
2. The solution is simple. Position a set of photoelectric sensors, mounted in a through-beam configuration on each side of the oncoming traffic lane. Be sure to position them about a half mile before the exit where the overpass resides. The photoelectric sensors may be mounted on metal poles at a height that is just lower than the maximum height for the overpass.
3. The output from these photoelectric sensors will operate flashing lights on a sign which should be positioned far enough after the poles that the driver of the offending vehicle will see them and be able to take the appropriate exit in order to bypass the hazard. The sign should offer explicit instructions to the driver warning them to exit immediately when lights are flashing.
4. This solution has been used successfully in several applications and has completely removed the uncertainty for drivers as to whether they should proceed under an overpass with a tight fit or take the exit.

Tips & Warnings

• Always measure the height of your load just before departing.
• Pay attention to the posted maximum height for each overpass.
• This solution is to be used only as a supplement to assist drivers and should not encourage them to become less cautious!