Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Report
changing the availability of travel-time and delay information. A number of states now purchase
roadway speed data from private companies. These data are primarily available for Interstates
and other major freeways. Similarly, increasing emphasis on incident response, roadway
operations, and construction traffic management is likely to slowly increase the amount of data
available on traffic disruptions. However, considerable improvement will be needed in most of
these areas to fully deploy a performance reporting and management system that could improve
travel-time reliability.
Roadway Performance Data
Section 2 of the Phase 2 Draft Report for the SHRP2 L03 project (1) provides information about
the sources of and procedures related to performance data.
Existing and Future Performance Data
The current availability of travel-time reliability and roadway performance information is highly
variable across the country. Some performance statistics (e.g., traffic volumes) are widely
available in almost all areas of the country but often only describe routine conditions (average
annual daily traffic) and not the variation inherent in those conditions. Other statistics (e.g.,
average annual daily truck traffic) are generally available in all states but are often not available
in specific geographic locations (e.g., core urban areas, especially on arterials). Data on the
general patterns of traffic volume variation (time of day, day of week, seasonal) are available,
but not on a site-specific basis. Other performance statistics (e.g., travel times and travel-time
variability) are not widely available but exist in great detail in a few selected locations—
generally on instrumented freeways in major urban areas, or on roads leading to major tourist
venues.
However, modern technology is rapidly changing the availability of roadway-system
performance data. Data availability is expected to change dramatically in the next five years as a
variety of new data-collection technologies become available and are adopted by transportation
agencies. Examples of recent data technology include:
• Roadside infrared-sensing technology that allows the collection of detailed vehicle
classification data (truck volumes) on high-volume urban roadways without the expense
of manual data collection.
• A variety of new technologies (Bluetooth-based travel-time computation, multiple cell
phone–based vehicle probe tracking technologies, and GPS fleet tracking vehicle probes)
show significant potential to dramatically reduce the cost of travel time, speed, and delay
information.
• The I-95 Corridor Coalition recently completed acceptance testing of INRIX
Corporation’s near-real-time roadway speed data, which are primarily based on vehicle
speed data obtained from a variety of fleet tracking systems. These acceptance tests apply
to most of the major freeways on the Atlantic seaboard. USDOT is sponsoring efforts
through the American Transportation Research Institute (ATRI) to collect similar types
of data on major rural interstates throughout the country.
The result of these recent technology improvements is that in the near future, travel-time and
speed data could potentially be collected on most major freeway systems at a moderate cost, if
they are not already available through existing sources. What is unknown is whether roadway
agencies will have the discretionary funding to pay for the collection of these data. Similarly,
GOALS AND PERFORMANCE TARGETS Page 20