California Partners for Advanced Transportation Technology

This report is a deliverable of a project, TR0002, sponsored by the California Office of Traffic Safety, contracted through California Department of Transportation, and conducted by California PATH. Roadway incidents, besides their direct impacts of property damage, injuries and fatalities, can quickly lead to further congestion or even secondary incidents of nearby traffic. Due to the direct and indirect effects of incidents and congestion afterwards, it is important that post-incident handling proceed as quickly as they can. One primary factor in the delays of incident handling is the necessary and proper documentation of incident information for legal and technical reasons. The prevailing method of scene measurement is often conducted by physically walking the scenes with wheel measures or similar tools. The common method and its conventional approach present several issues: time consumption, road hazard, limitations at site, and needs of photographic evidence. The objectives of this application are to resolve some, if not all, of the aforementioned issues encountered typically at accident scenes. In this project, we investigated and developed a computer software application using photogrammetric techniques to facilitate the measurement of the aforementioned incident scenes. This software will allow the user to simply take one or a few photographs and extract all needed measurements in the convenience of the office, solving the shortcomings of the conventional method. Jointly used with other field tools deployed by CHP or Caltrans, this application aims at alleviating the burdens of on-site measurements and expediting the process of evidence gathering. Ultimately, the goal is to reduce the impacts of incidents on roadways thus leading to reduced congestion, smooth traffic flows, and enhanced public safety. From this exploratory project, we have developed a software application that improves upon a current method of roadway incident documentation. This improved method is advantageous since it is a non-contact method, allowing the incident scene to be undisturbed and also allowing difficult or almost impossible-to-measure scenes to be measured effortlessly. Also, the photographs serve as a permanent record allowing future measurements to be made. Finally, the amount time this method saves during each incident is important to quickly restore roadway conditions and thus help resume traffic flow.