Road construction has long been motivated by political goals, such as effectiveness, security demands and decentralisation. Also the environmental impact due to road construction should be taken into consideration. A great number of environmental assessment methods exist. The best method must be comprehensive but simple enough to use and to understand that it comes to general and frequent use.
This paper describes a method developed 1997 in a master thesis  by Johansson at Uppsala University of Technology in Sweden. The purpose of the thesis was to study which improvement method is the best one from an environment perspective. The methods were measured by several parameters i.e., ecological and human toxicity, energy consumption and emissions, all calculated to the life length of the road.