Traffic incident automatic detection algorithms by using loop detector in urban roads

This paper proposed an improved California Algorithm and recent patents for detecting traffic incidents in urban roads. Traffic incidents in urban roads contribute 50% to 60% of the total congestion delays. Incident detection involves the collection and the analysis of traffic data. The common loop detectors were selected as the collected tool in this research. The existing incident detection algorithms are more abundant, and mostly apply in freeways where the traffic flows are steady. The traffic incident detection algorithms in urban roads should be developed. Based on the existing detection algorithms, an improved California Algorithm was presented, which contained the adoptive dynamic threshold with the characters of traffic incidents and traffic flows in the road network. Further detection results of the improved California Algorithm were judged by the OD matching regularity of the volumes at the signal intersections to make the detection results fit with the actual flow feature. Finally, the data collected by loop detectors was used to validate the proposed algorithm. The results showed that the improved algorithm could predict the traffic incidents effectively, but there are still some false positives.