A core objective of the LTPP SPS studies is to understand and quantify the relationship between pavement performance, truck volumes, and axle loadings. The objective of this pooled fund study is to improve the quality and increase the quantity of monitored traffic data (volumes, classifications, and weights) at the SPS-1, -2, -5, -6, and -8 test sites. There are a total of 64 SPS-1, -2, -5, and -6 test sites and 20 SPS-8 sites throughout North America. This multi-year study will attempt to collect research quality data by installing a Bending Plate, Load Cell, or Quartz Sensor at as many of these SPS sites as economically possible. For the purpose of this study, research quality data is defined to be at least 210 days of data (in a year) of known calibration meeting LTPP's precision requirements for steering and tandem axles, gross vehicle weight, vehicle length, speed, and axle spacing.

This pooled fund study has two phases that run concurrently. Phase I consists of performing annual field calibrations and validations of Weigh-in-Motion (WIM) systems according to LTPP field procedures. All WIM systems must meet LTPP's precision requirements for steering and tandem axles, gross vehicle weight, vehicle length, speed, and axle spacing. Phase II consists of maintaining WIM systems installed by the Phase II contractor and performing daily downloads and verification checks of the data from these systems. The Phase II contractor is only responsible for maintaining and verifying the data from the systems they install under this project. Any WIM system installed by the highway agency using their in-house staff must be maintained by the highway agency. However, the Phase I contractor will perform the annual field calibrations and validations for all SPS WIM systems that are part of this study. We are currently in the second round of contracts for the Phase I and Phase II activities. The current Phase I contractor is Applied Research Associates (ARA), Inc. This five-year contract was awarded April 2010. The previous contractor was MACTEC Engineering and Consulting, Inc. The Phase II contractor is International Road Dynamics (IRD), Inc. As a result of the Phase II's contract obligation for the WIM systems they install, FHWA sought a sole source four-year contract with the Phase II contractor. The contract was awarded in September 2011. The funds contributed to carry out the work of this study are on current contract task orders. Therefore, this pooled fund study will end in April 2013. However, the LTPP program will continue the Phase I and Phase II activities as part of its program data collection activities. For those of you attending NATMEC next week, there is a 1-hour meeting on Wednesday, June 6 from 7-8 p.m. with the TAC members to discuss the status of this study. If you are not going to NATMEC, you will have another opportunity to get the