KENNEBUNK — A sure sign that spring is rapidly approaching can be found through the end of April in Kennebunk.

In an effort to limit pavement damage during the transition from winter to spring, the town has announced restrictions of roads in the area for certain trucks hauling heavy loads.

Posted roads are closed to nonexempt vehicles or combination of vehicles registered with a gross weight of more than 23,000 pounds. Two-axle trucks weighing between 23,000 and 34,000 pounds defined as carrying “Special Commodities” are exempt from the closures.

Representatives of Kennebunk’s Public Services Department said that the list of “Special Commodities” includes home-delivered heating fuel (oil, gas, coal, stove size wood that is less than 36 inches in length, propane and wood pellets; petroleum products; groceries; bulk milk; bulk feed; solid waste; animal bedding; returnable beverage containers; sewage from private septic tanks or portable toilets; and medical gases.

Postings shall remain in force except when the roadway is solidly frozen. A highway is considered solidly frozen only when the air temperature is 32 degrees or below and no water is showing in the cracks in the road and public works officials said that both conditions must be met.

Spring damage to roadways is caused by an upward movement of pavement as a result of the expansion of trapped water beneath the roadway surface, according to the Maine Department of Transportation.

Driving on roads containing trapped water can produce permanent damage to roads and crack pavement surfaces with differing levels of severity. Road distresses attributed to spring damage can impact road surface quality and are unpredictable and costly for towns and municipalities to repair.

MDOT officials say as spring temperatures warm and the ground thaws, the soil situated beneath roadway pavement becomes saturated with water, making it unstable and leaving many roads unable to support heavy loads.

Typically, a road that can easily handle a 15-ton weight in summer or winter may only be able to handle a 5-ton load during thawing. A posted road’s maximum weight limit is 23,000 pounds and it’s a temporary measure that’s designed to protect roads in vulnerable conditions.

Repairing or rebuilding a road damaged in this way can be costly, running as much as $1 million per mile in some cases.

When the ground begins to thaw and materials beneath roadway surfaces are saturated with moisture, travel over these roads can also cause cracking, potholes, and rutting.

Roads closed to trucks hauling heavy loads will remain unavailable until at least April 30 unless otherwise posted. Any violation of the rules is a traffic infraction punishable by a fine of not less than $250.

Kennebunk roads closed this spring to trucks with heavy loads include: Alfred Road from the intersection of Thompson Road to Cole Road; Old Falls Road; Cole Road; Old Port Road; Downing Road; Perkins Lane; Durrells Bridge Road; Ross Road; Emmons Road; Russell Farms Road; Harriseckett Road; Thompson Road; Heath Road; Winnow Hill Road; and Middle Road.

For more information about posted roads, call the Kennebunk Public Services Department at 985-4811.