Prepared in cooperation with the Indiana Department of Transportation and Federal Highway Administration. AbstractThere are about 46 weigh-in-motion (WIM) stations in Indiana. When operating properly, they provide valuable information on traffic volumes, vehicle classifications, and axle weights. Because there are great amounts of WIM data collected everyday, the quality of these data should be monitor without further delay. The first objective of this study is to develop effective and efficient methods to identify missing or erroneous WIM data. The second objective is to develop a data imputation method to update the missing or erroneous data.This report describes the WIM data checking process on both a monthly and a daily basis. The Weigh-In-Motion Daily Data Checking (WDDC) program is introduced. The whole procedure requires very little human intervention, and provides a convenient way to check daily summary data. This report also describes several imputation methods in the experiment of imputing 7-day data.