Adding Green Performance Metrics to a Transportation Data Archive

speeds in each lane. PORTAL also includes incident and variable message sign (VMS) data since 1999, 1 year’s worth of stop level bus data and hourly and daily weather conditions in Portland from automated weather stations. The four weather measures are temperature, visibility, wind speed, and rainfall. From the basic sensor data PORTAL computes four other measures using road segment length: vehicle miles traveled (VMT), vehicle hours traveled (VHT), travel time, and delay. The road segment length is the distance between midpoints from adjacent detectors. Delay calculation uses an assumed free-flow speed of 60 mph. PORTAL includes a set of tools for plotting these measures for different locations and corridors over a range of temporal aggregations (2). For assessing variability and reliability, PORTAL includes plots of mean values plus or minus one standard deviation, as well as mean and 95th percentile values of specific measures such as travel time. Other data sources are also being integrated into the PORTAL system, including freight weigh-in-motion data and statewide crash data. Efforts are made to minimize data errors and improve the quality of the measured data by identifying missing or erroneous data through error detection algorithms. Collected data fidelity is measured and reported in the system, enabling users to review the quality of the original data.