DENVER -- We've heard it before -- bridges and overpasses ice over first during winter storms. So this winter the Colorado Department of Transportation is testing two traction enhancement materials that could make driving over them much safer.

The overlay placed on the flyover bridge from southbound Interstate 25 to northbound Interstate 225 will incorporate granite chips into the pavement. The granite chips, along with a new automatic de-icer spray system, are supposed to improve traction in freezing conditions.

On the flyover from Parker Road to southbound I-225, CDOT will incorporate porous rocks into the road that will hold the de-icer product longer and give better traction.

"We apply the magnesium chloride or other liquid de-icer to the bridge and it soaks into the stone and then as it snows, the stone disperses the product out through the stone so it helps keep that ice bond from forming on the bridge," said Roy Smith, CDOT acting Maintenance Superintendent.

As part of the traction control improvements, CDOT will be installing two new automatic de-icing systems. One will be on the flyover bridge from southbound I-25 to northbound I-225. The other will be in the tunnel from southbound I-225 to southbound I-25.

Smith said, "As soon as the de-icing system registers any ice forming it applies just enough magnesium chloride to break that ice bond. So when our trucks go over the bridge they don’t need to apply more liquid over that bridge so we don't have over application and save money and resources."

While the traction material will be in place and tested this winter, the automatic de-icing system won't be installed until spring.

To ensure the bridge decks are treated in time for the winter, crews will be working over the next three weekends and have that part of the $1.5 million project complete by the beginning of November.