TYLER, TX (KLTV) - On your drive home, you may have noticed the black tubes placed across certain roadways.
These pneumatic tubes are a way for the Texas Department of Transportation to measure how much traffic comes through a certain area.
"These are used to determine the average daily traffic on roadways," TxDOT public information officer Kathi White said. "And that's used by different entities, for planning, for funding, for design, all different types of capabilities."
The pneumatic tubes will be place at 6,400 locations throughout multiple counties.
"Anderson, Cherokee, Gregg, Henderson, Rusk, Smith, Van Zandt and Wood," White said.
Drivers will notice either a single or double tube, both have different meanings.
"So when it's the one tube, it's looking at the volume of traffic, so just when an axle goes over it.," White said. "When there's the two tubes, it's kinda looking at vehicle specific, so it knows if it's a car, if it's a truck."
While there are plenty of places to find the pneumatic tubes, don't expect to see them in the same place for long.
"Basically the tubes are out for a 24-hour period, and removed," White said. "You know it's just constantly moving from location to location."
But as they move you are still bound to see them around the district.
"I know if I leave here and get out on the loop, there's one that's right not to far from here."
The pneumatic tubes will be placed throughout the district until April 26. Then TxDOT will analyze the date and make decisions accordingly.