Advanced traffic management systems allow video image detection to supplement and improve data inputs in transportation modeling efforts. Video detection systems use machine vision technology, the interaction of video cameras, and specialty computer hardware and software to measure traffic. Traffic parameters such as hourly flows, density, vehicle speed, level of service, and other parameters derived from measured and default values are automatically computed. However, the accuracy of video image detection systems is dependent upon factors such as the camera height, location, and angle above the roadway. Environmental factors such as rain, sun intensity, and day/night also affect vehicle detection accuracy.