Goal

North Carolina and Ohio state troopers have reported significant weight disparities between inner and outer tires on CMVs by using a new scale that can measure weight on individual tires. The project goal is to statically weigh a statistically significant number of Class 8 CMVs utilizing per-tire weight scales and determine the extent of the reported issue. In addition to weighing trucks, an inspection will be conducted to determine the condition of the tires and suspension system of the vehicle. Additional information will be collected about the vehicles under inspection including brand, model, year, and mileage (if applicable).

Summary

A team of researchers will travel to five geographically separated weigh stations and weigh a minimum of 80 trucks in each location with scales that can measure the weight of individual tires. In addition, an inspection will be conducted of the vehicle noting tire pressure, age, suspension system issues/repairs, etc. The VIN number will be read to capture the vehicle make, model and age. The collected data will be analyzed to evaluate the initial claims and, if applicable, look for the sources of weight disparity (e.g., vehicle age, damage, weight distribution of load if visible, etc.)

Impacts

Vehicles that are carrying weight unequally across the tires have decreased stopping power and decreased roll and maneuvering stability (10 tires in strong contact with the road surface instead of 18). In addition, if some tires are carrying greater weight, this most likely will exceed the tire weight bearing ratings causing tire failures. Decreased breaking power, reduced stability, and tire failures increase the potential for crashes which result in property damage, injury, and fatalities. Having knowledge of the current situation can inform inspection criteria, rulemaking, and future vehicle design changes.