PROBLEM/SITUATION: Traditional methods of gathering evidence at scenes of serious highway accidents contribute to traffic congestion and delays.
SOLUTION: Modified surveying systems capable of electronically measuring, recording, and generating data faster, more accurately, and in less time than it takes using traditional methods.
JURISDICTION: Kentucky State Patrol; Minnesota State Patrol; city of Stockton, Calif., Police; Kalamazoo County, Mich., Prosecutor's Office; Lexington County, Ky.
VENDORS: MJC & Associates; Sokkia Instruments.
CONTACT: Mike Capman, president, MJC & Associates, 823 Parchmount Ave., Kalamazoo, Mich. 49004-1738. 616/344-3575.
A multi-car collision involving fatalities turns an interstate highway into a parking lot for hours, sometimes days. Much of the delay results from the necessity of collecting legal evidence relating to the accident, a process known as forensic mapping. It usually involves sketching vehicle and body positions, measuring the length and direction of skid marks, diagramming elevations, intersections, curves, and the natural and constructed features of the immediate area. With conventional tools -- pad and pencil, 100-foot steel tape and measuring wheel -- the process is tedious, limited in accuracy and scope, and painstakingly slow.
Lt. Robert Miller of the Kentucky State Patrol explained that the cost of traffic delays resulting from post-accident investigations can be substantial. "The federal government figures that while the police are gathering evidence and reconstructing an accident scene, delays are costing taxpayers $8 per vehicle for every hour traffic is stalled. Another study shows that commercial truck operators lose $1 a minute sitting in traffic. In northern Kentucky, up around the greater Cincinnati area, more than 16,000 vehicles an hour go through one stretch of I-475. If we have to shut it down eight to 10 hours for an accident involving several vehicles, we are talking about astronomical numbers."
Since hand-drawn maps and diagrams made at the scene are, by necessity, rough and hurried, an officer will most likely spend time at the station redoing them with ruler and compass to make them more presentable to the courts. The officer's time, Miller believes, would be better spent patrolling the highway.
In response to the need for faster, more accurate methods of gathering evidence, some law enforcement agencies and investigators have begun using a modified version of a surveyor's "total station," a system capable of electronically measuring and recording distances, angles, elevations, and the names and features of objects. Data from the system can be downloaded into a computer for display or printed out on a plotter. In negligent homicide and vehicular manslaughter cases requiring reconstruction of the crime scene, some courts now prefer the precision, scope and professional appearance of exhibits collected and generated by the electronic system.
HOW IT WORKS
There are basically four components of the forensic mapping system: a base station, prism, data collector and tripod. The prism, positioned at a desired spot, reflects an infrared beam back to the tripod-mounted base station, where a microprocessor automatically calculates distance, height and angle, and sends the information to the data collector. To identify the locations, features and objects being measured, the user selects codes from the data collector's built-in library. Measurements are referenced to geographic coordinates by positioning the base station over a known point, such as a manhole cover, fire hydrant or surveyor's brass monument.
The data collector is later downloaded into a PC, running software that translates the file into language used by a simplified CAD program. Other software allows the operator to put in titles and legends and identify all types of objects -- trees, buildings, vehicles, bodies, blood, guns, etc. -- with appropriate symbols. The result is a comprehensive map that can be scaled to any size and displayed or printed out on a plotter. When integrated with GIS and GPS, forensic data may assist state engineers and investigators in pinpointing high accident locations and