Ada County Highway District

ACHD's Road Wizard Sunday, December 8, 2019 ACHD's Road Wizard

Slippery slope at Can-Ada and New Hope Road; Is the blue-dyed salt and magnesium chloride used to treat snow and ice on the roads safe

The Road Wizard Replies

Dear Road Wizard: The intersection of Can-Ada Road and New Hope Road is a 4-way stop at the bottom of a very steep hill without much runout. In addition, there's heavy vegetation limiting sight lines across the northwest corner of the intersection, so eastbound traffic can't see southbound traffic until the cars are at the stop sign. When there is hard-packed snow or ice that's not been removed, it means southbound cars often cannot safely stop for the sign. Either they brake too hard, and end up sliding off the road while descending, or they don't brake hard enough and end up sliding through the stop. Are there any plans to address the safety of this intersection?

Paul

Road Wizard:

My crystal ball is not showing any crash history at this intersection dating back ten years, and emergency services have not been called out, as far as I am able to tell.

ACHD crews make areas with steep grades one of their top priorities for treatment prior to and during a winter weather event to minimize snow and ice buildup on the roadway. Sight distance is applicable to an uncontrolled intersection, which this is not. At an all-way stop, drivers need to see conflicting traffic at the intersection, so there is no code violation being presented.

As for future plans for this intersection, there is nothing on the horizon unless a nearby developer is required to make significant changes. The Farmers Union Canal is located just under a quarter mile north of this intersection (and about 100 feet higher in elevation), so the southbound downhill grade is unlikely to be changed approaching New Hope Road.

Dear Road Wizard: Tell me about the salt and de-icing that is being used on our roads. Does it really make that much of a difference?

Mary

Road Wizard:

This time of year, you will see blue salt, sand, and lines of liquid on the roads. This is all part of the safety measures that ACHD uses for winter weather. The lines of liquid are magnesium chloride which is used prior to a storm as an anti-icing agent and helps prevent falling snow from sticking to the road surface. As snow falls, salt and sand will be applied and crews will plow snow and slush from the roadway. All of this is a delicate balance - too much salt and sand cause a need for more sweeping later in the season and can negatively affect storm drain systems.

Many studies have been performed on what is the best management practice for winter maintenance, which are used to create guidelines for salt/sand and magnesium chloride use based on road temperature. These guidelines are followed by ACHD for snow and ice control.

Here are some numbers that did not come from my crystal ball but are from a Marquette University study. The proper use of road salt resulted in:

  • Crashes reduced by 88%
  • Injuries reduced by 85% 
  • Accident costs reduced by 85%

The blue dye in the salt is safe and helps ACHD crews identify where salt has already been applied, so they do not double up on their efforts.

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