Keeping the roads safer in winter
Posted on 22 August, 2011 in Stornoway Maintenance News
Commuting to work in winter can be hazardous in areas prone to snow and ice. With Tasmanians in the middle of a bitter winter, keeping the roads open and safe is a prime concern to both state and local government.
Typically, ice treatment is reactive. During cold weather, you may have heard on the radio that a road is being ‘gritted’. After an early morning inspection of an ice-prone area, grit will be spread across the ice patches to provide greater skid resistance to vehicles.
Cars crossing the grit can help break up the ice but it’s not considered an ideal treatment as the grit can then become a hazard on the road once ice has melted.
Preventative ice treatment is widely recognised as the best approach. Stornoway introduced a chemical ice treatment – calcium chloride – to Tasmania, with it now widely used to stop ice formation. The treatment was trialed several years ago with Hobart City Council during winter.
The trial demonstrated that ice consistently didn’t form in sections treated with the calcium chloride spray and as a result, Stornoway began working with the council to maintain ice affected roads.
So how does it work?
The calcium chloride is used to prevent frost forming and water freezing on the road. It’s basically a chemical reaction that reduces the freezing point of water.
It works in much the same way as common salt but is less corrosive and also continues to melt snow at temperatures well below where salt is effective.
In fact, a report commissioned during the trial showed that the calcium chloride was 90% less corrosive than salt when mixed at 25% strength. The solution used to prevent ice formation is typically only 15% strength which means it is even less corrosive.
Studies by the University of Tasmania at the time also demonstrated that the calcium chloride didn’t have any adverse impacts on the environment, on soil or surrounding vegetation.
Stornoway also developed temperature sensitive ice signs to assist motorists in knowing when temperatures where suitable for the formation of ice on the roads. These road-side signs have flashing lights which are activated when the temperature drops below zero (and ice formation is likely) and switch off at 5 degrees when the road should be ice-free.
The warning signs have been adopted by the state government and are now present on many roads in southern Tasmania, warning motorists to take care as ice is present.