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North Dakota Pilot GPS Project. Presenter: Judy L. Froseth Lory Harsche. The Problem:. Crash location information has been maintenance intensive and difficult to code. Engineering staff has expressed concerns with these problems. GPS Pilot Objectives:. Collection
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North Dakota Pilot GPS Project Presenter: Judy L. Froseth Lory Harsche
The Problem: • Crash location information has been maintenance intensive and difficult to code. Engineering staff has expressed concerns with these problems.
GPS Pilot Objectives: • Collection • Ensure the data format is accepted and usable • Test data entry screens for data acceptability • Test data retrieval to ensure proper format • Ensure data collection is simplified • Easy use of GPS units • Quality instructions provided to the officers
GPS Pilot Objectives: • Collection (continued) • Collect 500-750 crash reports with GPS data • Ensure significant quality of crash reports in pilot • Review the handwritten data format for correctness • Ensure GPS unit provides data consistent with data standard • Check GPS unit configuration options for consistency • Ensure data is collected when the GPS unit has a strong signal lock
GPS Pilot Objectives: • Collection (continued) • Collect law enforcement officers’ feedback • Discuss GPS use, function, performance, questions, issues
GPS Pilot Objectives: • Use • Import/export crash data into a GIS system for analysis, testing and review • Provide the system with GPS and crash report data • Review the export/import process for efficiency, make changes • Use electronic and paper node maps to compare GPS and node point location data • Provide feedback to officers
GPS Pilot Objectives: • Use (continued) • Have experts examine the data results to ensure data meets accuracy requirements, is consistently collected and is usable • Assemble the panel of experts • Determine what is required to analyze the data • Review the analysis, make recommendations to correct problems • Discuss statewide implementation
GPS Pilot: • Revise the MVCR form to provide space for GSP coordinates • Required close communication between: • Traffic Safety • Planning and Programming • Information Technology • Form was revised and printed in December 2001
GSP Pilot: • Two law enforcement agencies: • Bismarck Police Department in January 2002 • Cass County Sheriff’s Office in February 2002
GSP Pilot: • GPS Units: • Magellan Meridian GPS at $235 each
GSP Pilot: • GPS Units: • Garmin eTrex Legend at $265 each
GSP Pilot: • How did officers view this “extra” duty? • As part of the crash data collection process to provide more accurate data • Collection of GPS data became part of their daily routine • Which GPS units were preferred? • All officers preferred the Megellan, based on ease of reading the numbers
GSP Pilot: • GPS Unit: • Magellan Meridian GPS at $235 each
GSP Pilot: • How has the durability been? • There have been no known issues • What have been the pitfalls/problems? • GPS units provide a continuously reading number • Officer must select the 5th decimal digit from a fluctuating readout • The 5th decimal represents roughly 1-5 feet of change
GSP Pilot: • Have officers reported difficulty receiving signals/getting a reading? • One crash report indicated a reading was not possible due to heavy rains • Officers are not returning to the scene when the report is completed elsewhere
GSP Pilot: • What is the battery life? • Battery life depends on frequency of use • Bismarck PD uses about 2 sets per month • Cass County used original batteries for over 4 months
Technical Field Accuracy Comparison: • Manufacturer’s specifications on accuracy: • Magellan Meridian GPS • WAAS enabled up to 3 meter accuracy • Garmin eTrex Legend • 3 Meters – 95%, 15 Meters – 5%
Technical Field Accuracy Comparison: • Field Accuracy Test Comparison • Based on 5 random locations near the Bismarck Capitol • Tests were performed in a side by side comparison mid-day June 5th • Trimbal Pro/XRS GPS unit was used as the comparison
Technical Field Accuracy Comparison: • Radial difference in feet from the point identified by the Trimbal: Maximum Minimum Average Magellan 52 feet 16 feet 24.8 feet Garmin 36 feet 1 foot 16.2 feet
Data Collection/Preliminary Results: • As of July 26, 2002, 300 total crashes have included GPS data • About 30% of crashes reported by the 2 agencies have GPS coordinates • Initial analysis identified data collection/entry errors, requires a check • A non-labor intensive checkpoint process is being worked out