The U.S. highway system is continuously experiencing heavier and more frequent commercial truck traffic. Simultaneous to the increase in heavy vehicle miles traveled, the issuance of permits for overweight trucks has grown by more than 13% since 1997 (AASHTO/FHWA, 2007). The census bureau estimates that in New York State, the Vehicle Miles Traveled (VMT) by trucks weighing over 26,000 lbs increased by 15.7% from 1997 to 2002. These trucks’ VMT was estimated to be on the order of 1,767 million miles in 2002. The permit trucks’ VMT was estimated to be 110 million miles while the VMT of trucks that violated the weight limits was estimated as 5.4 million miles. Thus, according to the census bureau, overweight trucks would be responsible for about 6% of the total miles travelled on New York highways. However, because of the limitations of the weight enforcement process, it has been suggested that the actual percentage of the total mileage of overweight vehicles is much larger than the survey numbers suggest and could be in the range of 15% (Strauss and Semmes, 2006).

The high volume of overweight permit and illegal trucks is disproportionately increasing the damage to the U.S. and New York State highway infrastructure system and reducing the service lives of bridges and pavements.(Strauss, and Semmens, 2006; Roberts et al 2005). Overweight trucks also cause a significant and disproportionate amount of damage to pavements. Although legal truck traffic accounts for a large percentage of damage to highway pavement, the percentage of damage caused by overweight permit and illegal trucks is much greater than the expected damage from legal trucks. (Strauss, and Semmens, 2006; Roberts et al 2005)

It is important that the New York State Department of Transportation (NYSDOT) be able to estimate the impact and cost implications of the damage caused by overweight vehicles in order to maintain the safety of the system and develop effective infrastructure management and rehabilitation strategies. In particular, developing a mechanism to evaluate the damage and cost impact of overweight trucks will help NYSDOT personnel manage their permit issuance practices, establish permit policies and procedures, and devise weight enforcement strategies.

Research Objectives

The objective of this project is to develop models for assessing the cost of damage caused by overweight vehicles to New York State’s highway pavements and bridges. The models shall be applicable for assessing the cost of NYSDOT permit vehicles for both divisible and non-divisible loads including superloads as well as illegal trucks. The models shall be implemented in computer programs that can be used by NYSDOT personnel to help in the analysis of the effects of different overweight vehicles on pavements and bridges.

The research team shall meet the objectives by first reviewing recently developed methods for assessing the costs of damage to pavements and bridges. Recent studies that describe how these methods have been implemented shall be reviewed. In the next step, the researchers shall identify the best approaches that would be applicable to New York State infrastructure based on the information available on truck overweights, as well as bridge and pavement types and configurations. Subsequently, the researchers shall use the best approaches to quantify the damage and associated costs due to different categories of heavy trucks including: 1) Trucks satisfying the legal weight limits; 2) Permitted overweight divisible load vehicles; 3) Special hauling vehicles; 4) Special Hauling Superload vehicles; and 5) Non-permit trucks violating the legal limits or trucks violating their permit limits.