Updated Analysis of Michigan Traffic Inputs for Pavement ME Design
|Contract Number:||Contract 2013-0066 Z8|
|Keywords:||Pavement-ME sensitivity, pavement analysis and design, traffic inputs, rigid and flexible pavement performance.|
The purpose of this study is to characterize traffic inputs in support of the new Mechanistic-Empirical Pavement Design Guide for the State of Michigan. These traffic characteristics include monthly adjustment factors (MAF), hourly distribution factors (HDF), vehicle class distributions (VCD), axle groups per vehicle (AGPV), and axle load distributions for different axle configurations. Weight and classification data were obtained from 41 Weigh-in-Motion (WIM) sites located throughout the State of Michigan to develop Level 1 (site-specific) traffic inputs. Cluster analyses were conducted to group sites with similar characteristics for development of Level 2A inputs. Also, PTR locations with similar attributes were grouped for developing Level 2B traffic inputs. Traffic data from all freeway and nonfreeways sites were averaged to establish the statewide Level 3A inputs. Finally, traffic data from all sites were averaged to develop the statewide Level 3B inputs. The effects of the developed hierarchical traffic inputs on the predicted performance of rigid and flexible pavements were investigated using the Pavement-ME. Based on statistical and practical significance of the life differences, appropriate levels were established for each traffic input. Specific recommendations about frequency of updating road groups, and additional WIM locations in different regions are included in the report. The methodology for developing traffic inputs is intuitive and can be adopted by MDOT for future updates.