At its meeting today (Feb. 7), the Wright County Board of Commissioners undertook an annual rite of passage – approving spring weight restrictions for vehicles during an eight-week period in the spring. Wright County Highway Engineer Virgil Hawkins said the purpose of the spring load restrictions is to protect the roads when they are their most vulnerable.
“This is an annual thing that we do,” Hawkins said. “It’s meant to protect the investments we’ve made in our highway system. During the spring thaw, the moisture content in the gravel under the pavement is really high and it weakens the pavement – making it more susceptible to damage. So, every year we put restrictions on our highway system to preserve the life of our pavement.”
When Hawkins started his Wright County Highway Department career more than 25 years ago, most of the roads in the county system had 5- or 7-ton spring restrictions. But, as the system has been improved over the years, there are only four small segments with the 5-ton restriction remaining and almost all of the system has either a 9- or 10-ton spring restrictions.
Because spring weather is unpredictable and can vary greatly from one year to the next, the Highway Department seeks permission from the county board to approve the load restrictions in January or February.
“We ask for the permission from the board to approve the road restrictions at this time of year because when we’re going to put them on can vary by weather,” Hawkins said. “Most years they start in mid-March, but we’ve had a couple of years when they were put on in February because of warmer weather. When the restrictions are put on, they last for about eight weeks.”
Over the previous six years, there has been general consistency, but never two that were identical from the time the restrictions were started and ended – 2015 (March 12-May 7), 2016 (Feb. 29-April 15), 2017 (Feb. 21-April 17), 2018 (March 16-May 11), 2019 (March 19-May 14), 2020 (March 9-May 4), 2021 (March 5-April 26) and 2022 (March 18-May 13).
Typically, when the Minnesota Department of Transportation announces load restrictions for its different zones, counties in that area follow suit. Prior to 2022, Wright County was in the Central Zone. It is now in the Metro Zone, which typically enacts its spring load restrictions about a week earlier than the Central Zone. The announcement of spring road restrictions comes 72 hours before the restrictions take effect and the Minnesota State Highway Patrol and Wright County Sheriff’s Office enforce those restrictions by weighing vehicles that may be over the posted limit.
The duration of the restrictions has as much to do with the cold of winter as the thaw of spring. In bitterly cold winters, the ground under roadways can freeze more than six feet deep. Typically, the frost depth is closer to four feet. As of earlier this week, the depth was 36 inches and the coming warmup this week will lessen that quickly.
Thawing makes roadways more pliable and subject to cracking, which is why the restrictions are so important to preserving the pavement and preventing damage to the roadways while they are the most vulnerable. It may be an inconvenience to some truckers, but it can add years to the life of roadway and replacement costs keep rising.
To see the Wright County Highway Department website page dealing with spring load restriction information and the 2023 restriction map, click here: http://www.co.wright.mn.us/904/Spring-Load-Restrictions