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Using Cell Phone Technology to Collect Travel Data
D. Kyle WardMay 11, 2011
• Intro to Tech and Pilot Program
• Application to MPO Business Model– Congestion Management Process– Travel Demand Modeling
• Pilot Results
• Future of the Technology– Origin-Destination Estimation– Viability vs. Competing Technology
Outline
• 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– Demographics
Intro to Tech
• 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
Speed Pilot
• Congestion Management Process– Yearly data collection program– Before and After Metrics– Congestion Monitoring– Project Identification– Project Programming
Application to MPO
Application to MPO
• Travel Demand Modeling– Validation of Speeds and Travel Time– Volume-Delay Functions
• Accurate Free-Flow Speeds• Speed data matched to counts
Pilot Results
5:30 pm
Pilot Results
4:15 pm
• First signs of slowing– I-40 at Wade Avenue– US 70 between Lynn
and Millbrook
1/6
4:30 pm
• Bottleneck at Wade
2/6
4:45 pm
• Queue backs up along I-40
3/6
5:00 pm
• I-440 begins to slow
• I-40 congestion worsens
4/6
5:15 pm
• US 70 bottlenecks
5/6
5:30 pm
• Delay peaks on all routes
6/6
Pilot Results
• Speed profiles– Peak vs All Day Congestion– Weekend Congestion
• Concerns– Validation of Results?
• Purchase from different vendor/tech
– Default speed data capped at speed limit• Poor posted speed data impacts results• Uncapped speeds prone to outliers
– Solution: establish reference speeds
Pilot Results
• Modeling of Non-Recurring Congestion– 5-minute interval data reporting
• Origin-Destination Estimation– Currently being piloted by the MPO/Airsage– Requires enormous amount of observations
• Currently not possible with GPS
– Estimation of all trips, regardless of purpose
Future Applications
Competing Tech
• Infrastructure-based monitoring– Example: Bluetooth
• Expensive• Limited Coverage
• GPS– More accurate– Less samples (but growing)
• GPS-enabled devices doubling every year?
