Performance of A Low Cost System For Automated Documentation Of Crash Scenes Using GPS (AutoDOCS-GPS)

Charles Rodgers, Robert Nelsen, Darrell Greenlee, Theodros Assefa and Andrew Smith

Abstract:	OPTIMUS Corporation, under a contract to the National Highway Traffic Safety Administration (NHTSA), is developing a low cost (< $1.5k), automated, automotive crash scene, documentation system that utilizes the GPS for rapid, accurate measurements. NHTSA performs research on the causes and circumstances of automotive crashes in order to promote safer roadways and vehicles. An important source of data for this research comes from the analysis of crash scenes. The position and orientation of vehicles relative to each other and roadway features are important to determining the crash dynamics and cause. Currently, crash scene measurements are done manually with wheel and tape measures. The data are recorded by hand and the analysis is done through manual calculation. The results of the measurements and calculations are captured on two-dimensional drawings developed by hand. The number of manual operations in the measurement and analysis are a source of inefficiency and errors. In addition, data and sketches recorded on paper are difficult for the researchers to access, correlate, manipulate, and analyze. OPTIMUS is integrating a low cost system for a laptop computer that addresses these inefficiencies and inaccuracies by automating the entire process. We have developed a Kinematic Differential GPS subsystem to measure, record, and process the scene measurements as the user walks about the scene. The custom software links each measurement, as well as digital pictures, to scene elements, and can guide the user through the crash scene measurement process. Once the scene dimensions are determined, a Computer Aided Drafting (CAD) program is called to automatically construct a scene drawing using predefined scalable, graphical crash scene elements. An automated report generator then enters the scene data into a standardized text report complete with hyperlinks to the digital pictures. The report file, threedimensional scene data, and CAD file can be stored in various formats, and transmitted, retrieved, manipulated, and analyzed as any other computer file. The paper discusses the system architecture, processing software, and simulation results. The performance of the new system has been compared with current methods as performed by expert police officers on simulated scenes. The process and results of the two methods are evaluated to quantify the improvement in accuracy and efficiency provided by AutoDOCS-GPS. Results show that the AutoDOCS-GPS is three to five times faster than current methods, possibly significantly reducing traffic delays when used by local authorities. Each mile of traffic backup on a major highway costs the economy millions of dollars in lost productivity and fuel, and increased pollution, in addition to the psychological toll the frustration causes on the public. To date, the measurement errors of the new system’s kinematic Kalman Filter have averaged in simulations 1.2 cm for scene element points, which is less than half of the resolution of the current method without even considering human measurement and recording mistakes. These accuracy and efficiency improvements combined with the electronic format of the data will greatly enhance NHTSA’s capabilities and the capabilities of local authorities.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	509 - 516
Cite this article:	Rodgers, Charles, Nelsen, Robert, Greenlee, Darrell, Assefa, Theodros, Smith, Andrew, "Performance of A Low Cost System For Automated Documentation Of Crash Scenes Using GPS (AutoDOCS-GPS)," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 509-516.
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