Proactive Visibility and Underride Protection: RoadLites’ Approach to Trailer Safety

A trailer should be easier to recognize before a collision—and better equipped to protect people if one occurs. Those are two different parts of safety.

Underride guards address what can happen when a smaller vehicle strikes a trailer. Required lamps and reflective markings help other drivers identify it. RoadLites’ supplemental outline lights, along with the side-skirt lighting kits we’re developing, focus on adding visual definition to the trailer’s shape in low light.

We think of that as a proactive layer: giving other road users more visual information while there is still time to respond. It does not replace the impact protection provided by a structural guard.

What the underride debate reveals

The Wabash underride case brought renewed attention to rear impact guard design after a 2019 collision that killed two people. A jury returned a $462 million verdict in 2024. The award was later reduced, and Wabash reported settling the case in October 2025.

The crash happened in daylight. We cannot claim RoadLites lighting would have prevented it or changed the outcome. The case does show why safety discussions need to address both the chance of a collision and the harm a collision can cause.

In 2022, NHTSA strengthened its standards for rear impact guards. The agency also began examining potential side underride guards. As Heavy Duty Trucking explained, the final rule covered rear guards; side guards were a separate subject of research and discussion.

The proactive layer: defining the trailer’s shape

At night, another driver needs to understand more than the fact that a trailer is present. They need to judge where its side and rear extend.

Required marker lamps and retroreflective markings provide essential cues. Supplemental lighting can add visual definition when it is designed and installed appropriately. That is the purpose of RoadLites outline lights: to help make parts of a truck or trailer’s outline more apparent in low-light conditions.

We’re also developing side-skirt lighting kits. A side skirt runs along a substantial portion of the trailer, making it a natural area to explore for added visual definition. The kits are being developed as lighting products; we’ll share their specifications, compatibility, and installation guidance when they’re ready.

A lit aerodynamic side skirt is not a structural side underride guard. The lights do not make the skirt capable of stopping an impacting vehicle, and we do not claim they have been proven to prevent underride crashes.

The impact-protection layer: what happens if a collision occurs

Even a clearly marked vehicle can be struck. Driver distraction, speed, road conditions, and human error all affect what happens on the road. A FreightWaves opinion article argues that distraction deserves more attention in the side-guard debate. Advocates for stronger guards emphasize that impact protection matters because crashes can still happen.

Rear underride guards and potential side-guard designs address the collision itself. Supplemental lights do a different job. Better visibility cannot be treated as a substitute for a guard, and a guard does not eliminate the value of making a trailer recognizable.

Responsible lighting is part of the approach

More lights are useful only when they convey clear information. RoadLites outline lights and future side-skirt lighting must work alongside required lamps and reflective markings, without replacing or obscuring them.

In its 2025 interpretation responding to RoadLites, NHTSA explained why an auxiliary lamp’s color, location, brightness, and activation matter. The agency addressed the specific design submitted and an alternative color arrangement; its letter was not a blanket approval of every installation.

Safety needs both approaches

Proactive visibility aims to help people recognize a trailer before a collision. Impact protection aims to reduce harm if a collision happens. Neither can do the other’s job.

RoadLites is working on the visibility side of that equation. Our outline lights—and upcoming side-skirt lighting kits—are intended to make more of a trailer’s shape apparent in low light, as part of a broader approach that includes required lighting, reflective markings, attentive driving, and properly maintained impact guards.