Minnesota, United States
Documentation and Assessment of Mn/DOT Gate Operations
Summary Information
In Fall 1998 and between March and August 1999, Mn/DOT's Office of Advanced Transportation Systems conducted analyses to document past procedures and to identify current operational issues associated with gate systems. A benefit-to-cost analysis compared potential savings to estimated costs, and a winter storm case study compared costs for clearing a gated highway section to costs for clearing a section without gates.
FINDINGS
An analysis of gate operations during a severe winter storm was also performed. On November 11, 1998 a snowstorm prompted closure of Interstate 90 between the South Dakota state line and US Highway 75, while US Highway 75 remained opened between the Iowa state line and Trunk Highway 268. Comparative data from Mn/DOT reports are shown in Table 2.
Table 2: Comparison of Interstate 90 and US Highway 75
 |
Costs
|
|||||||
|---|---|---|---|---|---|---|---|---|
|
Plow Route
|
Lane Miles
|
Number of Plow Passes
|
Labor Hours/Miles Serviced
|
Labor Hours/ Lane Mile
|
Labor/ Lane Mile
|
Equipment/ Lane Mile
|
Material/ Lane Mile
|
Total/ Lane Mile
|
|
I-90
|
50
|
4
|
0.10
|
0.38
|
$9.08
|
$6.14
|
$4.50
|
$19.72
|
|
US 75
|
59
|
10
|
0.04
|
0.41
|
$9.98
|
$9.54
|
$4.59
|
$24.12
|
Two hundred lane miles were plowed on Interstate 90, while 590 lane miles of Highway 75 were cleared. Because Interstate 90 was closed, there was no interference from vehicular traffic and less snow compaction. Thus, the interstate was cleared to bare pavement four hours before Highway 75. As a result, total costs to clear Interstate 90 were 18 percent lower than costs to clear Highway 75.
