An important question in winter road maintenance is how it can be made more energy efficient. VTI research Anna Arvidsson has made a literature review and summarized several of the factors that affect how, when and where the winter road maintenance is performed. One of the factors that account for the greatest uncertainty in terms of winter road maintenance is the weather. This is an area that has a need for more research.
First and foremost there are sensors that measure the weather on the road and close to the road. A RWIS outstation (Road Weather Information System) measures many parameters, such as road surface temperature, air temperature, relative humidity, precipitation and type of precipitation and wind speed and direction. Using the measured parameters together with weather forecasts it is possible to determine when and where the action is needed. The development of sensors is constantly moving forward, twp recent Swedish examples are BIRDS that measures the freezing point temperature on the road and RoadEye that identifies the road condition.
When you know what action to take, it is time to make a route planning to ensure that the correct action is done on the right place at the right time.
What equipment is best suited for the performance of winter road maintenance, depends on the type of action that needs to be performed. An attachment to a plough truck that is well suited for one road might be less efficient on another. There are new plough trucks that can run faster than their predecessors and therefore the fleet can be reduced and thus energy can be saved.
Spreading of salt and sand could be more efficient by using different computer programs that calculate the amount of salt/sand that is needed, but also which routes are the most suitable to drive.
The location of the salt/sand storage affects the driving distances i.e. fuel consumption, and if it is possible to place the repository at an appropriate place in the beginning of an optimally planned salt-/gritting route the energy expenditure would be reduced. If it is necessary for a replenishment of material to cover an entire route, a lot of energy could be saved by having storage along the route to avoid deadheading.
One of the factors that account for the greatest uncertainty in terms of winter road maintenance is the weather. The past two winters, 2009/2010 and 2010/2011 have been cold, with lots of snow, which has required significant resources for winter road maintenance. The Swedish climate is changing towards warmer temperatures with more precipitation as a result according to UN and IPCC. This should lead to a decreasing winter road maintenance in southern Sweden (fewer days with cold temperatures), while northern Sweden may need more maintenance on the grounds that the number of really cold days will decrease and there will be more days with risk of slippery roads. This is an area that has a need for more research.
This literature review is focused on winter road maintenance, but might as well apply to railway concerning many issues.