Overview
There is a potential to reduce energy use of traffic by performing maintenance measures that lower the rolling resistance. However, the overall aim should be to decrease the total energy use in a life cycle perspective, including energy for both traffic and maintenance. When choosing maintenance alternative, it is also of importance to consider the costs involved. Pavement management is focused on keeping wide spread road networks in acceptable condition given certain budget constraints. Therefore, the economic constraints need to be addressed and in the case of choosing a maintenance alternative that reduces total energy, it also has to be cost-efficient in order for it to be performed.
The main scope of the research presented in this report is to investigate how road management should act to reduce total energy use of roads, including traffic and maintenance induced energy use, while also taking cost efficiency and the aspect of uncertainty into consideration.
The purpose is to enable a better consideration of the total energy used and maintenance cost when managing the road network.
The objective is to derive a meaningful instrument for decision making situations such as when selecting and designing maintenance treatments, in which total energy use and maintenance cost is considered.
A general method is developed and presented. A criterion, CR, has been identified for how to choose a pavement maintenance strategy in regards to cost and energy efficiency. A cost benefit analysis approach using Benefit to Cost Ratio, BCR, has been adopted.
Results
The study indicates that it is difficult to establish a simple rule of thumb. However, the CR-value may be a useful criterion in some circumstances and it is important to have guidelines as decision support where assessments are made of the road surface characteristics, total energy use and maintenance cost and where the different aspects are valued. This is especially important on an object level.
The effect of traffic energy use due to snow and water on the road surface was estimated. The possibility for taking these aspects into consideration when deciding on a strategy for an energy- and cost effective pavement maintenance is limited.
In summary, snow should not be accounted for, but the presence of water on the road surface could be a variable to consider. Moist has a non-negligible effect on fuel use and it is also to some extent dependent on the road surface conditions. However, how this should be done is not considered in the report but it could be interesting to investigate further. It should be emphasized that decision on which maintenance alternative to choose must, in the long run, be based on a broader perspective than just energy and maintenance cost and should also include other aspects of sustainability and safety.