Why Underride Crashes Are So Deadly
When a passenger vehicle strikes the side or rear of a semi-trailer, the car's hood and windshield can pass under the trailer body. The trailer edge impacts the passenger compartment at roof height, bypassing the vehicle's crash protection systems entirely. The result is catastrophic — decapitation, crush injuries, and traumatic brain injury are common.
Three Types of Underride Crashes
- Rear Underride: A passenger vehicle rear-ends a slower-moving or stopped trailer. Federal law requires rear underride guards, but many do not meet adequate force standards.
- Side Underride: A passenger vehicle strikes the side of a trailer during a turn or lane change. Side underride guards are not federally required, despite their proven effectiveness.
- Override: A truck drives over a smaller vehicle from behind. The passenger vehicle is crushed from above.
Liability Theories
Underride cases often involve multiple defendants and overlapping theories:
- Driver Negligence: Failure to signal, illegal lane changes, stopped on roadway without hazard lights.
- Carrier Negligence: Inadequate driver training, failure to equip trailers with adequate guards, deferred maintenance.
- Manufacturer Liability: Trailer manufacturers who sell underride guards that fail at highway impact speeds.
- Maintenance Failures: Missing or damaged reflective tape, non-functional trailer lights, corroded guard brackets.
Evidence We Preserve
Evidence Preservation Is Time-Critical
Trucking evidence can disappear quickly. Dashcam footage, telematics, ECM data, and maintenance records may be overwritten or discarded unless preservation begins immediately.
Call (405) 759-0515 to send a spoliation letter now →- Trailer and guard inspection: Physical measurement and engineering analysis of the underride guard before it is repaired or scrapped.
- ECM / black box data: Speed, braking, and throttle data from the truck in the seconds before impact.
- Maintenance and inspection records: Guard installation date, repair history, and compliance with FMVSS 223/224.
- Scene reconstruction: Gouge marks, debris field, and lighting conditions.
- Dashcam and nearby surveillance: Video from the truck, other vehicles, and roadside cameras.
Federal Underride Guard Standards
FMVSS 223 establishes strength requirements for rear impact guards, and FMVSS 224 requires their installation on most trailers. However, these standards have not been updated to reflect modern crash forces, and side underride guards remain optional. We work with engineering experts who can demonstrate that a guard meeting minimum federal standards was still inadequate to prevent the underride.
⚖ Request a Free Case Review
If you lost a family member in a truck underride crash, we will investigate the guard, the carrier, and every entity in the chain of liability.