Q: Within the last three months my husband and I and two of our relatives have purchased new tires. We all have different brands of tires. We have all had the experience of driving where there is cement on the interstate that has wavy ridges. All of us have felt like we are hydroplaning when there is not water. The cars do not hold the road like they should. My sister asked a tire dealer about it and he said that it would be the same with any new tire, but should be better as the tires wear. Personally, I don’t understand if roads shouldn’t have that surface or if the tires are the problem.

A: “Before I was in my current position, I helped manage the store in Mountain Home for five years,” said Nate Baer with Les Schwab. “While I was there I-84 was being re-surfaced with the new grooved style concrete. While different cars and different tires all handle differently, we absolutely noticed that there was a consistent issue with vehicles experiencing a hydroplaning effect after having new tires installed, and only on the new grooved concrete on I-84 through Idaho. New tires do have deeper tread obviously than a worn tire, which does seem to amplify the problem. This problem only became worse after the speed limit was also increased on these stretches of freeway. Occasionally we would find a different brand or model of tire that would drive better for different cars, but generally speaking it was a consistent problem no matter what type of tire was installed.”

Nathan Jerke with the Idaho Transportation Department said there may be correlation between tread width and the width of the grooves that enhances the effect, but it doesn’t seem to be universal for all cars or tires.

“The section of roadway that we receive the most questions of this kind is along Interstate 84 between Boise and Mountain Home on a section of concrete roadway that was completed about five years ago,” Jerke said. “In this section the grooves in the roadway – which is called longitudinal tining – run parallel to the roadway centerline but can give a vehicle the feeling of slight side to side movements.”

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“Tining is completed to finish the concrete roadways before the surface ‘cures’ – or hardens. The contractor uses spring steel tines to place the grooves about three-quarter inch apart and three-sixteenths inch deep in the fresh concrete,” he said. “The tining provides texture to the surface and is added to concrete roadways for the primary reason to enhance grip between vehicle tires and the road. A minor benefit is that tining can also assist in helping direct water away from the roadway, enhancing grip when wet or icy.”

“On some concrete roadways, the tining is placed perpendicular to the lane, extending side to side on the road,” he said. “Tining in this direction provides the same benefits but at high speeds produces much more noise from the friction of the tires and a loud humming in the cab of a vehicle. Many people complained about that affect as well so it is utilized more often in lower-speed areas. With the longitudinal tining, the concrete workers attempt to make these grooves as straight as possible. The final finish may look great to the naked eye but might not be perfectly straight, which results of a slight motion experienced by many drivers at high speed.”

“There isn’t any data to support a crash history, but it does not appear that the grooves have caused any crashes,” Jerke said. “However, the grooves can give an uncomfortable feeling to drivers that feel they don’t have control.”

Have a question? Just ask and we’ll find an answer for you. Email your question to Kimberly Williams Brackett at timesnewscuriousmind@gmail.com with “Curious Mind” in the subject line.


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