Grooves on highways drain water, stop hydroplaning

QUESTION: On the new Powers Boulevard extension, the northbound section of the road has paving with parallel grooves (as if a fork had been run over the asphalt). This is similar to the paving done on the newer section of Interstate 25 north of Castle Rock. I find this grooved paving very difficult to drive in my subcompact car because the grooves seem to pull on my tires and I must fight for control of the steering wheel. When I drive it in a larger car I do not feel the wheels pulling against the steering. The southbound section of this road does not have the same type of paving. Why are they using this on the northbound portion only?
- Bonnie Plucinik

ANSWER:In this area, one lane is concrete and the other is asphalt, enabling the Colorado Department of Transportation to study both surfaces side-by-side for several years to determine which wears better.

The grooves, called tining, are being studied as well, according to Bob Wilson of CDOT. Tining allows water to drain from the roadway and helps decrease hydroplaning by eliminating the excess water between tires and the pavement.
Wilson says the grooves are 3/4 to one inch wide and the tread of some tires apparently matches the width of the groove. The problem you experienced seems to disappear as the tining wears down.

Wilson said CDOT is they are researching several different groove patterns and a concrete section of road in that area is not tined, to provide data.
According to CDOT, California experienced a 70 percent reduction wet-highway accidents on tined roadways.