The purpose of this report is to examine the current state of commercial vehicle data handling in an effort to identify ways in which the Arizona Department of Transportation's (ADOT's) practices can be improved. This is done through a threefold approach that includes a literature review, survey of other states' practices, and an ADOT needs assessment.
The Traffic Monitoring Guide (TMG) provides a method for the development of a statistically based procedure to monitor traffic characteristics such as traffic loadings. Truck weight data in particular are a major element of the pavement management process because there is a strong relationship between pavement deterioration and truck weights. Because truck weight data collected by weigh-in-motion (WIM) systems are more representative of actual traffic loadings and are more efficient than enforcement and static weight data, the use of the TMG and WIM systems together provide improved monitoring of truck weights. The objective of this research was to develop a plan for VDOT to implement a truck weight sampling procedure using the TMG and WIM systems. Four alternatives from the TMG that were based on different schemes for multiple measurements at permanent WIM sites were evaluated. A truck weight sampling plan was developed for the preferred alternative. Truck weight sample sites, data collection procedures, cost and resources estimates, data from permanent WIM sites, and data management information are included in the plan.
"This synthesis will be of interest to planners, pavement designers, administrators, and others interested in knowing the actual weights of vehicles using the highways. Information is presented on current uses of weigh-in-motion systems that can obtain the data needed to properly plan and design highways."--Avant-propos.
Transportation agencies tasked with forecasting freight movements, creating and evaluating policy to mitigate transportation impacts on infrastructure and air quality, and furnishing the data necessary for performance driven investment depend on quality, detailed, and ubiquitous vehicle data. Unfortunately, commercial vehicle data is either missing or expensive to obtain from current resources. To overcome the drawbacks of existing commercial vehicle data collection tools and leverage the already heavy investments into existing sensor systems, a novel approach of integrating two existing data collection devices to gather high resolution truck data - Weigh-in-motion (WIM) systems and advanced inductive loop detectors (ILD) is developed in this dissertation. Each source provides a unique data set that when combined produces a synergistic data source that is particularly useful for truck body class modeling. Modelling truck body class, rather than axle configuration, provides more detailed depictions of commodity and industry level truck movements. Since body class is closely linked to commodity carried, drive and duty cycle, and other operating characteristics, it is inherently useful for each of the above mentioned applications. In this work the physical integration including hardware and data collection procedures undertaken to develop a series of truck body class models is presented. Approximately 35,000 samples consisting of photo, WIM, and ILD signature data were collected and processed representing a significant achievement over previous ILD signature models which were limited to around 1,500 commercial vehicle records. Three families of models were developed, each depicting an increasing level of input data and output class resolution. The first uses WIM data to estimate body class volumes of five semi-trailer body types and individual predictions of two tractor body classes for vehicles with five axle tractor trailer configurations. The trailer model produces volume errors of less than 10% while the tractor model resulted in a correct classification rate (CCR) of 92.7%. The second model uses ILD signatures to predict 47 vehicle body classes using a multiple classifier system (MCS) approach coupled with the Synthetic Minority Oversampling Technique (SMOTE) for preprocessing the training data samples. Tests show the model achieved CCR higher than 70% for 34 of the body classes. The third and most complex model combines WIM and ILD signatures using to produce 63 body class designations, 52 with CCR greater than 70%. To highlight the contributions of this work, several applications using body class data derived from the third model are presented including a time of day analysis, average payload estimation, and gross vehicle weight distribution estimation.
