Connected vehicle technology is helping the Michigan Department of Transportation (MDOT) clear snow and ice from roadways faster, making winter a little easier for drivers, while saving taxpayers’ money.
MDOT originally started installing GPS-based automatic vehicle location (AVL) devices on its winter road maintenance equipment in 2013. These systems report where each truck is, and they gather data from other sensors to report details such as atmospheric conditions, camera images, and speed and salt application rates for each vehicle. MDOT then feeds that information, plus additional pavement and weather data and forecasts, into its maintenance decision support system (MDSS), which it uses to better plan for winter storms, providing a powerful combination for managing plowing and salting operations. MDOT has now installed AVL/GPS on all of its plows and some of the state’s county road commissions are also using the technology. With multiple systems in use, MDOT and the counties are collectively researching how to expand the deployment of the technology while coordinating and standardizing its use.
AVL and MDSS have helped MDOT reduce salt consumption, contributing to an estimated 2.2% increase in efficiency. The agency spends about US$30m on salt in an average year, so even modest reductions in salt use save a lot of money. MDOT operations and maintenance engineers are continuing to improve the system interface to show more detail and more accurate locations, and they expect even greater efficiencies as they gain experience with the system. With cost-savings and safety in mind, MDOT promotes a number of best practices to boost salt use efficiency during winter maintenance. The department is encouraging its drivers to drive mroe slowly when possible while applying salt, so more stays on the road. MDOT is also investigating new application systems to keep the salt from bouncing out of driving lanes. Other ‘sensible salting’ solutions include: setting application guidelines for winter conditions, using weather stations to better target areas that will benefit most from salt, and pre-wetting the salt so it sticks to the road and starts working faster.
In the interest of safety, there are occasions when MDOT and its contract county road commissions and municipal public works departments will refrain from salting. During normal winter conditions, when temperatures are between 20-30°F, salt works well for melting snow and ice, so plows can more easily blade it from the roadway. Below 20°F, however, and salt takes longer to work, and may increase the speed at which roads refreeze. Below 10°F, the roads refreeze even faster, making them icier than if salt had not been applied, so in those conditions, sand is used instead.
“‘Monitoring snowplow speeds and material application helps us apply efficient salting practices,” said Melissa Howe, region support engineer for MDOT’s maintenance field services section. “‘Maintenance supervisors can also easily adjust shifts based on the timing of a storm, so we have plows on the roads precisely when they’re needed, adding people proactively rather than reactively.”