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Facts About Probe Data
Based on a Study by General Motors in 2004-2005,
to support a real-time traffic information system
based on probe vehicles:
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at least 3% probe samples or 5
million probe vehicles are required to cover
freeways in the US , while more than 5% or
8-10 million probe vehicles are required to
cover major surface streets in the US ; |
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for top 10 metropolitan areas in the US,
at least 2.3 million probe vehicles are
required to cover freeways and at least 3.8
million probe vehicles are required to cover
major surface streets; |
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for top 30 metropolitan areas in the US,
at least 3 million probe vehicles are
required to cover freeways and at least 6
million probe vehicles are required to cover
major surface streets. |
Sources:
- Journal of Intelligent Transportation
Systems, Volume 9, Number 1, January-March
2005
- US Census 2000
- US Bureau of Transportation Statistics
- Based on a Study by the University of
California at Berkeley in 2000, to support a
real-time traffic information system based on
probe vehicles in the San Francisco Bay Area,
5% samples or 300,000 probe vehicles are
required to cover freeways.
Sources:
- PATH, University of California at Berkeley
, Working Paper, PaperUCB-ITS-PWP-2000-18,
2000.
TCI Probe Technology
To improve model accuracy, TrafficCast
International is currently incorporating floating
vehicle data (FVD) collected using GPS devices,
Wi-Fi Hot Spot technology, and cellular probe
technology. Having adopted the probe data
technologies from the ADVANCE Project (the largest
traffic probe demonstration project in the US from
1991-1996 with a price tag of $50M), the
TrafficCast International's models have designed
modules to accommodate the latest input from probe
vehicles. In strategic partnership with China
Mobile and TrafficCast China, TCI has deployed the
largest cellular probe system in Shanghai (http://www.trafficcast.com/news_06.11.01.htm),
which produces travel speed and travel time
information in real-time by using cellular probe
data and 10 million China Mobile subscribers in
Shanghai.
Currently, due to its limited sample size and
limited coverage in terms of time and roads, the
GPS probe data mainly function as historical
benchmark. As more GPS probes are deployed and
integrated into the data stream in the next 3-10
years, GPS probes will start to function more as a
real-time input for real-time and predictive
traffic flow data. However, this process is
lengthy and requires significant investment by the
industry.
On the other hand, cellular probe data could
become a viable alternative to provide both
real-time and historical flow data in the next 1-3
years. Because the cost to deploy cellular probe
is much less than GPS probe and the time to
provide large coverage is also much shorter. As
part of its historical flow database, TCI
integrated GPS probe data generated by fleet
companies. However, the impact of GPS probe data
will be limited until larger samples are available
in real-time.
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