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Implementing Cell & GPS Data Sets D. Kyle Ward May 3, 2012. Outline. Intro to Tech Application to MPO Business Model Congestion Management Process Travel Demand Modeling Results Speed Origin-Destination Concerns Looking Forward. Review of Cell Tech.
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Outline • Intro to Tech • Application to MPO Business Model • Congestion Management Process • Travel Demand Modeling • Results • Speed • Origin-Destination • Concerns • Looking Forward
Review of Cell Tech • Uses cell-tower triangulation to locate cellular devices • Similar to GPS, but less accurate • Ubiquitous cell phone use compared to GPS • Numerous metrics can be estimated • Speeds • Origin – Destination • Demographics
Review of GPS Tech • Targets mobile GPS devices • Smart Phones • In-vehicle systems like OnStarTM • Benefit/Cost • More accurate • Smaller sample size
Application to MPO • Congestion Management Process • Yearly data collection program • Before and After Metrics • Congestion Monitoring • Project Identification • Project Programming
Application to MPO • Travel Demand Modeling • Validation of Speeds and Travel Time • Volume-Delay Functions • Accurate Free-Flow Speeds? • Speed data matched to hourly counts • Origin-Destination Validation • In the future, this data could be used to support non-recurring congestion models
Cell Speed Pilot • Contracted with AirSage • 834 centerline miles of coverage • Significant arterial coverage • 24/7 for March, 2010 • Data scrubbed of personal information • Fraction the cost of traditional methods
4:15 pm 4:30 pm 4:45 pm 5:15 pm 5:30 pm 5:00 pm • Queue backs up along I-40 • First signs of slowing • I-40 at Wade Avenue • US 70 between Lynn and Millbrook • Bottleneck at Wade • Delay peaks on all routes • US 70 bottlenecks • I-440 begins to slow • I-40 congestion worsens 2/6 1/6 3/6 4/6 5/6 6/6 Speed Results Source: AirSage Cell Data
Speed Results • Speed profiles • Peak vs All Day Congestion • Weekend Congestion Source: AirSage Cell Data
Origin-Destination • Contracted with AirSage to perform OD • Research Project • Describe travel among ~200 Census Tracts
OD Comparison • Comparing three data sets • Expanded Household Survey • AirSage OD • Triangle Regional Model (version 5)
Target Area Downtown Raleigh, NC
Trip Totals • Total Trips to Downtown Raleigh
Trips to Raleigh, NC Expanded Household Survey
Trips to Raleigh, NC AirSage Expanded Survey
Trips to Raleigh, NC Triangle Regional Model (V5)
OD Conclusions • Discrepancies in total number of trips • AirSage seems to capture travel pattern • Want to re-run with new Verizon sample • Regional model “smears” trips • Other areas were tested where the three datasets aligned much closer
Concerns • Number 1 Concern: Privacy • Three key points • No personal data • Aggregated Data • Liability is with data provider – not user
Speed Concerns • Handling of Signal Delay • Cell data appears to capture • GPS does not (possibly too accurate?) • Speed Capping • Default datasets capped at posted speeds • INRIX global cap of 65 mph • Poor posted speed data impacts results
Looking Forward • Work continues with data companies • Remove speed caps • Capture signal delay • New cell products tested in other regions • Select link • Sub-area cordon surveys • Corridor surveys
Questions? • D. Kyle Ward, EI • Transportation Engineer • (919) 996-4395 • Kyle.Ward@campo-nc.us