The ability to monitor and adjust salt use has drawn environmental praise.
With the arrival of the season’s first snow, Anoka County put its cost-saving fleet of plows back to work Tuesday night, using high-tech tools to clear roads quickly and use as little salt as possible.
The 15-driver night crew is expected to salt and clear the county’s 1,656 lane miles, including turn lanes and shoulders, by Wednesday morning, said Jim Christenson, county maintenance superintendent.
The county has won awards for its forecast-based, ’round-the-clock plowing and for greatly reducing the amount of salt it puts down, said Doug Fischer, transportation division manager.
One big factor in the reductions was a relatively simple suggestion from a driver a few years ago: to adjust the dispenser dial settings in trucks so that salt could be applied in increments of 50 pounds per mile instead of 100.
Now all of the county’s 27 trucks have those settings, which saves about 75 pounds of salt per mile, Christenson said. Last winter, when plows were dispatched 86 times, about 3,225 tons less salt was dispensed than would have occurred with the old settings, he estimated. At $62 a ton, the county saved about $200,000, he said.
For reducing salt use and adding data recorders in trucks to monitor salt dispensing, the county Highway Department won an Environmental Leadership Award in 2011 from the Freshwater Society, a nonprofit Twin Cities group.
“We recognize government units that have done exemplary things to reduce road salt use without compromising safety,” said society President Gene Merriam. He also noted that wetting salt before it is applied, as Anoka County does, keeps it from bouncing off roads and reduces both the amount needed and harmful runoff into waterways.
Other local governments, including Hennepin County and the city of Coon Rapids, use similar salt-saving devices, as well as GPS and data recording systems such as those that Anoka County installed in 2009.
The county’s 27 plows are operated by a 15-person night crew and a 23-person day crew. If major storms hit, other workers can be called in to bring the total force to about 50, Christenson said.
Anoka County hired the same private forecaster used by the Minneapolis-St. Paul International Airport to provide tailored weather radar and outlooks, Fischer said. Highway supervisors monitor the forecasts on computer tablets.
“The supervisors can watch at home,” Fischer said. “Sometimes at night they set alarms each hour to see when the snow is coming and where it will hit the county. It’s a nerve-racking job to make the first call to get people out.”
Plow operators have a maze of dials, salt calibrators, temperature sensors and computer screens to monitor, not to mention road hazards and traffic.
“It’s like being an airplane pilot in these trucks,” Fischer said. “They are checking road temps and air temps. … If road temperatures get colder, they may dial up from dropping 200 pounds to 300 pounds” per lane mile.
‘We try not to waste manpower or materials’
The GPS allows supervisors to see where the plows are, Fischer said. The data also shows how much salt drivers dispense and how long they take on their routes. That information is used to coach drivers who may be laying too much or, occasionally, not enough salt, Christenson said.
“Accountability is the key,” he said. “We try not to waste manpower or materials.”
The latest improvement came last year when the department began regularly spraying a calcium chloride and molasses blend onto salt before it hits the streets, Christenson said.
The chemical solution is also sprayed from two tank trucks, especially on bridges and ramp loops, up to a day before snowstorms. The molasses — beet juice is also used — makes the salt stick to the roads, keeping them passable until operators can plow them, Christenson said. The calcium mix works below 15 degrees, when salt loses effectiveness, and melts snow to keep it from bonding to roads, he added.
Motorists seem to notice the highway department’s work.
“The number one thing the public compliments us on is snow and ice removal,” Fischer said.
Jim Adams • 612-673-7658