In February, a truck driver died when his tractor trailer crashed through the guard rail and went over the side of the Chesapeake Bay Bridge, plunging into the water. Many were quick to blame the crash on high winds when it came to light that just before the crash, a wind restriction prohibiting tractor-trailer traffic on the bridge had been lifted.

However, Chesapeake Bay Bridge-Tunnel authorities maintain the crash occurred due to the driver’s error in passing another tractor trailer – and was not wind-related. CBBT Police Chief Edward Spencer says the truck was in the right lane when the driver attempted to pass a tractor trailer in front of him. Upon returning to the right lane, the truck rode up onto the curb, went through the guard rail, and fell into the water below.

The incident raised questions about the safety effectiveness of current bridge-crossing restrictions. According to the Chesapeake Bay Bridge-Tunnel’s website, the bridge is subject to a six level scale for wind restrictions. The lowest level is Level 1, which places restrictions on certain vehicles when winds reach 40 mph. Wind gauges along the span send readouts every 30 seconds to computers monitored around the clock. If a gauge detects a problem gust, restrictions are put into place relating to the type of vehicle, the load and the weight.

On the morning of the accident, a storm with Level 4 gusts of 60 mph had closed the span to tractor-trailers. The Virginia-Pilot reports that the now-deceased trucker had called his company at 8 a.m. saying he was concerned about the wind. However, around noon, a Level 1 restriction was declared and the span was cleared for tractor-trailer traffic. Within the hour, winds had picked up enough to move to Level 2’s additional weight requirements, which the truck would not have met. A Level 2 restriction involves 47 mph winds and only tractor-trailers carrying at least 30,000 pounds of payload are permitted to cross. According to Police Chief Spencer, the tractor trailer in this crash was hauling 4,000-6,000 pounds. The truck driver attempted to cross the span in his rig during the short open window of the Level 1 restriction, following other tractor trailers that had been waiting in line due to the earlier Level 4 restriction.

Mike Crist, deputy director of infrastructure for the bridge says the guardrails that line the bridge are eight inches taller than required by federal guidelines. However, guardrails are designed to withstand a 62-mph impact from a smaller vehicle. A guardrail is not designed to stop a tractor trailer but to “give” and direct a vehicle back onto the roadway. A stronger guardrail could harm drivers of smaller vehicles due to its rigidity and would likely be ineffective in stopping the truck anyway.

The “black box” from the tractor trailer in the fatal crash was damaged and provided no data on the driver’s speed or actions prior to the crash. Although it remains unclear whether wind was a factor in this crash, Richard Wood, a consultant in truck aerodynamics, says the bridge-tunnel’s 52-year-old wind-restrictions scale may need to be updated to account for the weight and shape of newer trucks and trailers. Wood thinks the bridge-tunnel should reduce its speed limit during gusty conditions and institute other safety measures such as no passing, and spacing requirements between trucks.