In descending order, the top 10 factors coded for large trucks and their drivers were: · Brake problems · Traffic flow interruption (congestion, previous crash) · Prescription drug use · Speeding in hazardous conditions · Unfamiliarity with roadway · Roadway problems · Required to stop before a crash (traffic control device, crosswalk) · Over-the-counter drug use · Inadequate surveillance of road conditions  · Fatigue