North Dakota Pilot GPS Project

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North Dakota Pilot GPS Project

• Presenter Judy L. Froseth
• Lory Harsche

2
The Problem

• Crash location information has been maintenance
  intensive and difficult to code. Engineering
  staff has expressed concerns with these problems.

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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

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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

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GPS Pilot Objectives

• Collection (continued)
• Collect law enforcement officers feedback
• Discuss GPS use, function, performance,
  questions, issues

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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

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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

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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

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GSP Pilot

• Two law enforcement agencies
• Bismarck Police Department in January 2002
• Cass County Sheriffs Office in February 2002

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GSP Pilot

• GPS Units
• Magellan Meridian
• GPS at 235 each

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GSP Pilot

• GPS Units
• Garmin eTrex Legend at 265 each

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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

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GSP Pilot

• GPS Unit
• Magellan Meridian
• GPS at 235 each

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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

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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

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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
  

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Technical Field Accuracy Comparison

• Manufacturers specifications on accuracy
• Magellan Meridian GPS
• WAAS enabled up to 3 meter accuracy
• Garmin eTrex Legend
• 3 Meters 95, 15 Meters 5

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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

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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

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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

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