Highway Accident Report

Accident No.: HWY-98-SH-039
Accident Type: Loss of control on downgrade
Location: Dunlap, Tennessee
Date and Time: August 13, 1998; 7:13 p.m.
Vehicle 1 (V1): 1994 Peterbilt tractor-semitrailer hauling wood chips
Vehicles 2-10 (V2-V10): 4 passenger cars, 1 sport utility vehicle, 3 pickup trucks, and 1 panel truck
Fatalities/Injuries: 2 fatalities, 17 minor to moderate injuries

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Accident Description

The truckdriver was unable to control the vehicle's speed traveling down a steep, 4-mile downgrade toward a signalized intersection at State Highway 111 and U.S. Highway 127. (See figure 1.) She stated that she attempted to downshift into a lower gear. The driver failed to put the transmission back into gear, thereby descending the hill with only air mechanical brakes to control the speed. She lost control of the truck, traveled into the intersection, and struck several parked and moving vehicles and pedestrians. Two occupants of a car were killed; four other vehicle occupants and 13 pedestrians were injured.

The truckdriver stated during her interview with the police that her truck was overloaded (in excess of 93,000 pounds). A postaccident inspection of the truck revealed no mechanical deficiencies.

State/Federal Oversight

Tennessee has adopted the Federal Motor Carrier Safety Regulations with some variances; none of the variances were pertinent to the carrier or driver at the time of the accident. The Commercial Motor Vehicle Division of the Tennessee Department of Safety had never reviewed or audited either the owner/carrier of the truck tractor or the owner of the semitrailer involved in the accident.

Figure 1. Accident diagram.

Probable Cause

The National Transportation Safety Board determines that the probable cause of the accident was the truckdriver's inability to control the truck on a long, steep downgrade. Contributing to the cause of the accident may have been excessive load weight.

Adopted: September 17, 2002