Freeway incident detection through filtering

The structure and performance of existing freeway incident detection methods are reviewed and a new method is proposed. The new method reduces the likelihood of false incident decisions that occur during short duration traffic disturbances by smoothing detector occupancies. Temporal smoothing is performed by the statistical mean or median of a data window moved over time. The algorithm considers the smoothed spatial occupancy difference between detector stations, and detects an incident when the difference changes significantly in a short time period. The proposed algorithm and a set of existing algorithms are tested with traffic and incident data from I-35W in Minneapolis. Test results, expressed in tems of detection rate at indicative false alarm rates, demonstrate the improved performance of the new algorithm over previous algorithms.