Zero velocity and salt brine: One state garage's experience

Mark Sharrock
Coshocton County Manager
Ohio Department of Transportation, District 5
Jacksontown, Ohio

In 1998 the Ohio Department of Transportation's Coshocton County Garage, located in central Ohio about 50 miles east of Columbus, began testing and experimenting with innovative methods for improving the efficiency and effectiveness of their snow and ice removal program. Armed with one dual zero velocity spreader system (a unit designed for the direct placement of salt on the pavement in the opposite direction of travel and at the same speed of the vehicle to yield zero velocity or direct placement), the garage built a homemade brine-making system and began their journey of experiments of pre-wetted salt and dual zero velocity placement. To date, the garage has two anti-icing units and five trucks modified for the dual zero velocity application with plans to modify its remaining nine units over the next five years.

To understand the logic behind the mindset of moving to a total dual zero velocity and anti-icing fleet, one must look at the results as yielded through this type of application versus traditional spinner methods. Like all other agencies located within the central Ohio area, the garage typically used traditional methods of salting, sanding and, when determined by lower than normal temperatures, pre-wetting with liquid calcium chloride. During 1998, with only one dual zero velocity truck in use, the benefits of pre-wetted salt and direct application were obvious. It was quickly noted that not only could this single-axle unit easily cover the area traditionally requiring a tandem, but there was also a noticeable decrease in the amount of salt consumption (believed to be associated with both direct placement and the use of pre-wetted material). The following winter two more of the traditional spinner gates were replaced with dual zero velocity units that were equipped with on-board pre-wetting tanks. The results were impressive—bare pavement in half the time of other like routes while using 70 percent less salt.

Two years of experimentation were adequate to convince the staff that they were definitely on track for making enormous strides in the improvement of their snow and ice removal program. As brine use increased to 50,000 gallons the second year over 12,000 gallons used the first, the staff recognized the necessity to upgrade the brine-making system if they were to continue upgrading their fleet. Three years into the program the garage purchased and installed an automated brine-making system capable of producing 4,000 gallons of brine per hour, increased the dual zero velocity fleet to five units, and purchased two, 1,300-gallon capacity, liquid anti-icing units.

Over the past two winters the garage used over 330,000 gallons of brine and less salt than any other like county within their district. Conservative numbers for salt-savings dollars indicate the garage saved over $70,000 during the past two seasons. Data from last winter indicates neighboring counties, comparative in both lane miles and snow fall, used 50 to 300 percent more salt to achieve similar levels of service. As shown in Figure 1, 2001-2002 data indicates the cost per mile of dual zero velocity and salt brine to be about one-half the cost of traditional methods.

Much of the success of Coshocton County's ODOT garage can be accredited to the dedication of its staff. The operators are well trained in both the mixing of brine and the application of materials. They have eagerly experimented with and perfected applications for the variables within their equipment, routes and local weather conditions. Figures 2, 3 and 4 indicate associated production differences and material cost.

Word of the staff's success with their innovative approach is spreading throughout their seven-county district. To date, the Coshocton County folks have not only designed and built their own brine-making system, but have also assisted three of their neighboring counties with similar systems. In addition to the brine-making systems, they have lent their talents and expertise to several of their neighbors with the design-build of numerous anti-icing systems for the direct application of brine. When winter does decide to arrive in this central Ohio ODOT district, each of its seven counties will be equipped with some type of brine-making system and an overall district total of 16 direct application anti-icing units.

In review of the benefits of this type of approach to snow and ice removal as compared to traditional methods, it is worthy of noting that with the use of dual zero velocity spreaders roads can be treated at speeds of 40-50 miles per hour while keeping up to 90 percent of the granular salt material on the road surface, in the wheel tracks where it is most effective. One can also cover twice the amount of lane miles in half the time as compared to the conventional systems while cutting salt consumption/use in half and still provide the same level of service. The effective treatment of pavements at high speeds provides less disruption to the traveling public, yielding overall improved customer service and satisfaction.

To reach Mark Sharrock, call (740) 622-2741 or send e-mail to msharroc@dot.state.oh.us.