ITD's rock patrols become essential highway safety practice

There’s nothing like a car-sized boulder resting in the middle of a highway to wreak havoc with your highway travels. Driving has its share of inherent risks, but ITD wants to do everything possible to remove dislodged rocks as a one of the hazards.

Preventing rockfall on Idaho’s highways is the driving force behind ITD’s annual spring maintenance activity – Rock Patrol. It is a critical aspect of the department's goal to improve driver safety. Falling rocks are an annual event. So, too, are the questions.

The questions are familiar – people wondering why they see ITD trucks with snowplows still attached patrolling bare highways.

Rock Patrol is the answer.

Behind the wheel of the plow is an ITD maintenance worker prowling for falling rocks, a hazard exacerbated by changing temperatures and moisture (from melting snow or spring rains), loosening ground that restrains hillside rocks.

“Some parts of our mountain roads have rocks fall on them virtually every morning and night,” explained Dan Bryant, southwest Idaho maintenance coordinator. “Rain, wind and temperature variations can bring them down in significant numbers.”

Crews still encounter snow at this time of year on some of the routes, and have the plow blade in place to deal with those occasional storms. But the chief benefit of a plow this time of year is that it can be used to move rocks that are four or five feet in diameter, as well as the little ones that can take out an oil pan on a car or truck, or flatten a tire on a small car, motorcycle or bicycle.

The point of performing rock patrols in plow trucks is not really about saving time, although that also occurs because a truck with an attached blade can address snowfall or rockfall immediately. Crews don’t need to return to a nearby maintenance facility to get a truck with attached plow blade and return to the scene.

Rather, the primary benefit is that “we can get the rock off the highway before someone hits it and is injured or damages a vehicle,” Bryant explained. 

Plow trucks are used primarily on stretches of highway with a history of rockfall, where the crews are likely to encounter rocks.

Published 3-29-13