MSU Study on Log Truck Accidents on Interstates in Mississippi 2014 to 2018
By: Dr. John B. Auel, Assistant Extension Professor, Department of Forestry, College of Forest Resources, Mississippi State University
July 17, 2020 - Introduction Forestry contributes an estimated $12.8 billion annually to the Mississippi economy . It is the second most valuable agricultural commodity. The average annual harvest of forest products from 2014 through 2018 is in excess of 31.5 million tons , with log trucks (includes trucks with log trailers, pole trailers, and chip vans) being the primary mover from the woods to the mills. Moving that volume of material requires over 1.2 million loaded trips per year, at an average of 25 tons per trip. Each loaded trip also requires an empty return, doubling that number to 2.4 million trips each year. If the average distance to the mill from the woods is 40 miles (80 miles round trip), each year log trucks travel 96 million miles transporting wood harvested in Mississippi.
Mississippi Log Truck Accidents from 2014 through 2018
According to the Mississippi Department of Transportation (MDOT), between January 1st, 2014 and December 31st, 2018 there were 1,376 accidents involving log trucks investigated by MDOT, for an average of 275 per year. MDOT provided GPS coordinates and accident descriptions to MSUES. The descriptions did not include detailed information but was the original form filled out by the officer on-scene. Information is lacking in most cases. Also, it is not possible to determine fault in many of the cases. Some are clearer than others though and some inferences can be made. Regardless of the lack of details, this information provides a decent window into issues with trucking in the state.
The actual volume estimates from MS Severance Tax data for the same time period, shows approximately 158.5 million tons of wood was harvested from forestlands in the state. At 25 tons per load for the average log truck, that is 6.3 million loaded truck trips, or 12.6 million loaded and empty trips from January 2014 through December 2018. Put another way, there was only one log truck accident, investigated by MDOT, for every 9,211 log truck trips in the state.
Interstate Accident Locations: Log truck accidents are uncommon on interstates, but the main reason for this is that they seldom run on the interstates when compared to other vehicles. Accident locations were uploaded to ArcGIS as a layer. This layer was placed on county and major highway layers to identify locations. The coordinates were not always accurate, so accident descriptions for each appearing to occur on an interstate highway were examined for specific road information. Only accidents that occurred on an interstate highway or ramp were included. Many accidents that appeared to be on the interstate highways occurred on surface streets adjacent to the interstates. These were omitted. For example, an accident that occurred on an off ramp where a truck rear-ended another vehicle at the end of the ramp was counted as part of interstate use accidents. An accident that occurred as a truck was turning onto a surface street after stopping safely at the end of the off-ramp was not counted since the accident was not integral to interstate use.
There was enough information contained in each accident description to categorize the potential cause and to make some assumptions regarding underlying causes. For example, broken drive shafts were listed under equipment as a primary factor. An underlying factor may well be maintenance. If nothing else, this will give the PLM program a chance to emphasize aspects of log trucking that need improvement.
Results: There was a total of 49 accidents occurring on interstates between January 2014 and December 2018. This represents 3.6% of all log truck accidents. The following table shows the number of accidents for each interstate highway in Mississippi. Click here to view the full study.
