NTSB Press Release

National Transportation Safety Board
Office of Public Affairs


May 14, 2002 

WASHINGTON, D.C. - The National Transportation Safety Board today adopted a final report on its investigation into a fatal highway crash in a work zone in Jackson, Tennessee, citing the truck driver's incapacitation and a flawed medical certification process as the probable cause. Poor coordination and planning for the work zone project by the Tennessee Department of Transportation, the Tennessee Highway Patrol and the construction contractor were found to be contributing factors in the crash.

On July 26, 2000, an eastbound tractor semitrailer traveling at a driver-estimated speed of 65 miles an hour entered a 55 m.p.h. work zone and collided with a Tennessee Highway Patrol (THP) vehicle protecting the work zone. Witnesses reported that the patrol car exploded and caught fire at impact. The patrol car was pushed approximately 192 feet before it came to rest on the median. The truck continued through the median and into the westbound lanes, where it collided with another vehicle. The State Trooper in the patrol car was killed in the crash. Witnesses saw the truck drifting out of its lane before the accident.

The medical oversight issues presented by this crash were similar to those dealt with by the Safety Board in its investigation of a fatal tour bus crash in New Orleans the previous year. The truck driver in the Tennessee crash had previously been diagnosed with sleep apnea and hypothyroidism, and had a similar crash in 1997, when he struck the rear of a patrol car in Utah.

Although neither condition is specifically disqualifying for a commercial driver's license, the Safety Board believes that had a comprehensive medical oversight program been in place at the time of the accident, this driver, with known and potentially incapacitating medical conditions, would have been less likely to have been operating a commercial vehicle. This accident, the Board said, "demonstrates how easily unfit drivers are able to take advantage of the inadequacies of the current medical system, resulting in potentially fatal consequences." The Board urged the Federal Motor Carrier Safety Administration and the American Association of Motor Vehicle Administrators to act quickly to develop a comprehensive medical oversight plan for commercial drivers.

Motorists had complained about the design of the work zone before the accident. The signage was poor and drivers were unsure which lane was closed. The Safety Board said that the traffic control and safety aspects of the work zone operation would have been improved had the construction contract incorporated traffic control plans for all aspects of the work zone operation and had it assigned specific responsibilities to each party. In fact, the Board noted, the traffic control configuration for this work zone did not meet federal guidelines for a lane closure on a divided highway. In addition, the Board stated that had the Tennessee Highway Patrol officers received work zone traffic control training, they may have asked for clarification on the traffic control strategy to be used that day, and would have realized the hazards of positioning their vehicles in the lane behind the highway construction vehicles.

Work zone fatalities have increased 52 percent over the latest five-year period recorded, from 717 in 1996 to 1,093 in 2000. Commercial vehicles, which account for 7 percent of all vehicle miles driven, are involved in 20 percent of all fatal work zone accidents. It is impossible to assess whether the increase in work zone deaths is due simply to increased traffic patterns or to other reasons because no adequate exposure data is available. The Safety Board continues to wait for a positive response to its decade-old recommendation to the Federal Highway Administration to collect work zone exposure data.

As a result of this investigation, the Board issued four safety recommendations to the Federal Highway Administration, the National Highway Traffic Safety Administration, the Tennessee Department of Transportation, and several associations to develop a model training program for law enforcement personnel that addresses traffic control strategies for work zones. The Board also recommended that FHWA review and revise the Manual for Uniform Traffic Control Devices to provide guidance on coordination with law enforcement personnel used in highway work zone traffic control.

A synopsis of the Safety Board's report can be found on its web site under Publications. The full report will be available on the web site in several weeks.

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NTSB Office of Public Affairs: (202) 314-6100



The National Transportation Safety Board (NTSB) is an independent federal agency charged with determining the probable cause
of transportation accidents, promoting transportation safety, and assisting victims of transportation accidents and their families.