ONE quiet Sunday morning in mid-August, the driver of a petroleum transport steered his rig onto the sweeping on-ramp that carries traffic from the westbound Bee Line Expressway in Orlando, Florida, to I-4 west. Seconds later, the rig had rolled over, spilling at least 8,000 gallons of gasoline.
Fire erupted almost immediately with flaming fuel coursing down the ramp, through a storm drain, and onto I-4 below. Subjected to intense 1700°F heat, the overpass began breaking up. In a chain-reaction series of accidents that followed the tanker rollover, two motorists died. Remarkably, the 31-year-old tanker driver walked away with a few broken bones.
Less than a week later, four days to be exact, another gasoline transport belonging to the same carrier overturned in Tampa, on the Florida Gulf Coast. This incident happened at about 6:30 am as the rig was turning right from westbound Gulf-to-Bay Blvd onto northbound US 19. Fortunately, cargo loss was limited to about 600 gallons, no other vehicles were involved, and the truck driver reportedly sustained no serious injuries.
A major petroleum refiner tallied up 31 rollover incidents worldwide in its distribution operations during 2001. Six of the accidents happened in the United States. Transportation managers at the petroleum company are concerned that they are seeing an upward trend in tanker rollovers, and they are not alone.
Members of the National Tank Truck Carriers (NTTC) Safety Council have similar worries. The rollover issue is on the agenda for all four NTTC Safety Council fall regional meetings. In addition, Safety Council members are calling for creation of an industry-wide database on tanker rollovers.
The database is to be part of a full-court press on the rollover issue. It would give the tank truck industry a chance to develop statistics that would help identify rollover trends. As one NTTC Safety Council member put it: “we're looking for the significant reasons for this rash of incidents.”
Despite the lack of conclusive proof at this time, safety managers have a number of theories about the primary causes of tanker rollovers. They point to four basic factors: excessive speed, driver inattention, driver fatigue, and inadequate training and experience.
With regard to excessive speed, drivers may be under the speed limit but operating too fast for conditions. Anecdotal evidence suggests that many rollovers occur at speeds below 30 miles per hour. However, that can be too fast on an exit ramp or in a sharp turn.
Cliff Harvison, NTTC president, suggests that a factor called speed adaptation may play a role. Drivers think they know how fast the truck is traveling by the way it feels. Studies show that today's trucks run so smoothly that estimates of speed can be off by 10 to 20 miles per hour. Errors get worse the longer a driver is behind the wheel.
Statistics show that driver inattention is a factor in 30% of vehicular accidents. How much does this contribute to tanker rollovers? Driver fatigue seems to have been a factor in some rollover accidents, but more information is needed. In the area of training, younger drivers may not be familiar with the slosh factor in partial loads.
Looking beyond truck driver error in rollover accidents, safety managers want to see what other factors may be involved. Among these are tire inflation, mechanical failures, routing, highway design and condition, and other motorists.
Building a tanker rollover database is an important proactive first step for this industry. Safety managers will have a crucial tool in their effort to reduce the potential for rollovers. They will have a better idea of how to train drivers in rollover prevention, and they will gain perspective on the potential for technology solutions.
The biggest challenge may be the development of a format that will ensure anonymity for the fleets that participate in the database. This is a key concern, according to those involved in the project, but it can be overcome.
It may be impossible to fully eliminate the potential for rollover accidents. However, NTTC and its Safety Council members are moving in the right direction. The tank truck industry must have accurate and timely information to address the rollover problem.