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HCTRA selects iWitness for improved crash scene documentation

Image-based 3D measurement technology improves safety on Texas Toll Roads

Bellevue, WA. – July 25th, 2007 - DeChant Consulting Services (DCS), provider of the versatile close-range photogrammetry system iWitness™, has announced the decision by the Harris County Toll Road Authority (HCTRA) to adopt iWitness as an important component of their standard operating procedure for accident reconstruction and scene documentation. iWitness will be used on the 103 miles of the toll road system. iWitness facilitates much faster accident scene recording and is expected to both significantly reduce road closure times for accident events and lessen the likelihood of secondary accidents.

Based on the success achieved by other state and local police agencies using iWitness, HCTRA officer’s on-scene documentation time is expected to be reduced by at least 50% as compared to traditional measurement methods.

Police investigators working the toll road join a list of DCS customers in Texas, using the iWitness photogrammetry software that include the Dallas County Sheriff’s Office, Arlington, Mesquite, Lewisville, N. Richland, and El Paso police departments.

The HCTRA contract awarded to DCS, included the iWitness photogrammetric software, special DCS designed photogrammetric markers, Crash Zone (diagramming software), Nikon digital SLR cameras and training of both software's as a complete turnkey system. Implementation of the technology is expected in 4th Q 2007.

With the iWitness technology, recording of a traffic accident requires only a consumer-grade digital camera and DCS-designed photogrammetric markers. After the very rapid image recording is completed at the accident scene, the 3D measurement phase is undertaken back at the office. This enables traffic disruption to be kept to a minimum and enhances safety for police and emergency services personnel, as well as motorists held up by the accident.

The iWitness process commences with police officers taking multiple images at the crash scene from different camera angles. These images are then processed within iWitness on a desktop or notebook PC to generate the 3D measurements of important features to support a dimensional reconstruction of the accident. This semi-automated process results in measurement accuracies that are generally around 1 inch over scene sizes of 100 yards or more. The robustness, reliability and accuracy of the photogrammetric measurement technology are an important factor for both accident analysis and any subsequent legal proceedings.

HCTRA police officers join a growing list of state police/patrols, county sheriff offices and local police departments around the country that routinely use iWitness. HCTRA follows the lead of highway patrols from Florida, New Hampshire and Minnesota to adopt iWitness as the primary measurement tool for 3D documentation of evidence and accident scene mapping.

“With this system, we won’t have to plot points at the scene and we just take pictures and pack up our stuff and do the work back in the office”, says PJ Brock, Senior Accident Investigator of the Arlington Police Department in Channel 5 and 11 television interviews that aired on three Dallas stations January 30th, 2007. Investigator Brock added: “it’s very dangerous to be out on the highway with roads shut down, especially at night when visibility is not good and you have the drunk drivers coming at you. For the public, of course, it helps open up the roadway faster for them to go about their business and not be stuck in a long traffic jam.”

Lee DeChant, President of DeChant Consulting Services, has implemented close-range photogrammetry systems across the US and believes iWitness is the optimal image-based mapping technology for accident reconstruction, based on its low-cost, robust online data processing and its simple operation. DeChant Consulting Services has assisted numerous state and local police departments to implement photogrammetry technology, as it becomes a standard for police accident documentation and forensic measurement.

About DeChant Consulting Services – DCS Inc

DeChant Consulting Services is the North American distributor of iWitness and offers turnkey photogrammetry solutions to a range of customers, including police and transportation agencies, accident reconstruction practitioners, industrial engineering firms and universities. DeChant Consulting Services is headquartered in Bellevue, WA.

More information about DeChant Consulting Services can be found at

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