TEMPLE — A pilot program using Interstate 35 in Temple will help the Texas Department of Transportation test a new variable speed limit system in construction zones, according to a TxDOT news release.
Interstate 35 in Temple is one of three major highways going to be used as test sites this summer. The others are I-20 in Eastland County and Loop 1604 in San Antonio.
Temple’s system will test congestion related to I-35 construction, while I-20 in Eastland County is specified to test weather conditions. San Antonio’s location will test general congestion, said Jodi Wheatley, I-35 spokeswoman for TxDOT.
Temple’s testing begins Monday and will continue for at least three months. After the initial testing phase is completed, the data will be analyzed and given to the Texas Legislature. Its next session begins in January. The legislators will then decide if this type of system for traffic control will be used throughout Texas, Wheatley said.
Variable speed limit signs are on northbound I-35 from about a mile south of Midway Drive to about a mile south of South Loop 363. The first sign will say “reduced speed ahead” and the next four signs will give stepped-down speed limits.
When conditions don’t require a change, the signs will show the normal speed limit, Wheatley said.
Adjusted speed limits are the maximum legal speed and should be obeyed the same as any other speed limit sign, according to TxDOT.
“The only allowed use of speed limits that change during the day is at school zones, and they are controlled by the time of day traffic around them is heaviest. Different school zones may have different times for the lower limits, based on traffic patterns in their area,” Wheatley said Thursday.
The new system’s purpose is to warn drivers of upcoming road conditions and traffic and will adjust speed limits using sensors and electronic signs.
According to the TxDOT news release, the system could become a model for additional roads across Texas, but Wheatley said she doesn’t know when the equipment will be placed.
Other states have used variable speed limit systems and been successful in reducing rear-end collisions and stop-and-go driving, according to TxDOT. Alabama, Delaware, South Carolina, Washington and Wyoming use the system, according to the Federal Highway Administration.
“The variable speed limit system also has the potential to reduce congestion by improving travel flow,” Wheatley said. “The maximum a limit can be lowered from one sign to the next is 15 mph. It will resemble the areas on country roads where speed limits drop as you approach a town.”
Traffic sensors along the road pick up factors such as construction, heavy traffic and weather conditions to show when a reduced speed limit could create safer road conditions. The use of portable signs lets speed limits be automatically reduced to gradually reduce the speed of traffic coming into a congested area, according to the release.
“Phased slowing like this is safer and allows traffic to slow without necessarily having to stop completely, giving it the potential to reduce congestion,” Wheatley said.
The Federal Highway Administration considered methods for improving traffic safety in wet weather conditions after the National Transportation Safety Board investigated a wet weather fatality accident on I-35 near Hewitt on Feb. 14, 2003.
One of the recommendations from the safety board was to find and eliminate locations with a high risk of wet weather accidents and then find a way to reduce the number of accidents. One of the methods explored is the variable speed limit system.