Impacts of posted bridges on log truck routing in Mississippi, USA

ABSTRACT

Log hauling costs are increased by the presence of closed and posted (restricted weight loading) bridges, as operators are forced to find alternative routes to wood-using mills. The USDA Forest Service Forest Inventory and Analysis (FIA) forest inventory, road network, bridge, and sawmill datasets were obtained for the US state of Mississippi. An 80.5 km buffer was established to define each sawmill’s working area, which occasionally extended across state lines. Anetwork analysis derived 129 feasible shortest optimal trucking routes between 46 FIA plot locations and the sawmills. Thirty of these routes had either closed or posted bridges along the shortest path; only 13 viable alternative routes were identified due to distance and posted weight limits. The additional trucking distance for these workable alternative routes averaged 7.1 km. The affected routes and their legal, full payload alternatives were each fitted to atriangular distribution to better understand how costs were impacted by posted or closed bridges. If no regulated bridges were encountered, haul cost across arange of haul rates and distances ranged from $3.50 to $14.40 USD per tonne. Costs were from $3.90 to $16.00 USD per tonne along routes with posted or closed bridges. On average, the cost difference was $0.98 USD per tonne, which was an increase of 12.0%. These findings have implications for road infrastructure maintenance, log trucking, wood procurement, and ultimately the values of standing timber and timberland.

KEYWORDS:

• Bridges
• network analysis
• road infrastructure
• timber transportation

Acknowledgements

Special thanks go to Drs. Bruno da Silva, James Henderson, and Mohammad Marufuzzaman for their input throughout the project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1. County governments per Mississippi Code § 65-7-45 may further regulate the GVW of any vehicle using public roads and bridges within their respective jurisdictions.

2. On July1, 2023, the gross vehicular weight limit for log trucks on state highways with aharvest permit was raised to 39.9 tonnes https://cdn.ymaws.com/www.msforestry.net/resource/resmgr/Mississippi_Harvest_Permit.pdf.

Additional information

Funding

This research was funded by the USDA Forest Service Landscape Scale Restoration Grant “Removing bottlenecks in the supply-chain of the sawmilling sector: Identification, improvement, & economic benefits”, [Award No.842057] Ms. Jessica Dilley with the Mississippi Department of Transportation kindly shared some of the data required to accomplish this work’s objectives.