In gasoline tanker accidents where the tanker rolls and slides over its top, the National Transportation Safety Board (NTSB) has documented a major protection problem with manhole guardrails. Our tests and other corroborative work show that the guardrails fail to protect because they are weak or because they do not provide enough protective clearance as the tanker rolls over. This situation often leads to major gasoline spills and fires.

In this case, a tanker on an interstate highway ramp had a tire blowout. The tanker rolled onto the earth near the highway, missing all obstructions; Figure 2 shows impressions documenting where the guardrails had hit the ground. Even though the rollover was at relatively low speed, manholes were mangled, thousands of gallons of gasoline were released, and the driver was very seriously injured in the ensuing fire. Our work included animated reconstruction and a series of guardrail tests. For more on the guardrail test program, click here.

The case settled quite favorably against the tanker manufacturer before trial.