Benefit

In Houston, a survey of motorists found that 85 percent of respondents changed their route after viewing real-time travel time information on freeway dynamic message signs.


May 2005
Houston,Texas,United States


Summary Information

In 1996, Transtar introduced a real-time traveler information system designed to automatically collect and disseminate travel time information to motorists in the Greater Houston region. The system used hundreds of roadside "EZ-Tag" transponder readers installed at 1 to 5 mile increments on area freeways to anonymously track the movement of millions of "EZ-Tag" transponder tags installed in motorist vehicles. The data collected were transmitted to a Transportation Management Center (TMC) where the information was further processed, converted into link specific travel times, and posted on area dynamic message signs (DMS).

The DMS system consisted of 81 dynamic message signs and covered approximately 250 centerline miles freeway in the Houston region. The automated system updated travel times every 10 minutes or less (between 5:30 am and 7:30 pm) whenever traffic congestion was detected.

In April and May of 2004, the Texas DOT (TxDOT) conducted a number of Internet-based surveys to assess customer satisfaction and examine the types of information drivers need in the Houston area.

The results indicated:
  • Real-time travel time information posted on DMS influenced drivers' route choice. Eighty-five (85) percent of respondents indicated that they changed their route based on the information provided (of this 85 percent, 66 percent said that they saved travel time as a result of the route change, 29 percent were not sure).
  • Overall, drivers were primarily interested in seeing incident information and travel time information. The following table shows the percentage of respondents that perceived positive benefits from specific types of DMS alerts.
TYPE OF DMS ALERT
PERCENTAGE OF RESPONDENTS THAT PERCEIVED POSITIVE BENEFITS
Incident alerts
93%
Freeway travel times
82%
Real-time road work advisories
81%
Future road work advisories
70%
Severe weather information
67%
Amber alerts
61%
Special event information
31%


In addition to travel time information, several other types of messages were posted on DMS. TxDOT used the following hierarchy to prioritize messages.

1. Incidents
2. Construction/pre-construction
3. Amber alerts
4. Travel times
5. Special events
6. Safety campaigns


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Source

Travel Time Messaging on Dynamic Message Signs - Houston, TX

Published By: Texas DOT and the U.S. DOT

Source Date: May 2005

URL: http://ops.fhwa.dot.gov/publications/travel_time_study/houston/houston_ttm.htm

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Notes

Benefit of the Month for September, 2007 !


Typical Deployment Locations

Metropolitan Areas

Keywords

DMS, CMS, VMS, Changeable Message Signs, Variable Message Signs

Benefit ID: 2007-00304