How long do transport infrastructure last: evidences from Norwegian roads and rail network

How long will transport infrastructure generate benefits for the society (the appraisal period) is an essential assumption in transport appraisals. However, there are considerable differences in the recommended appraisal periods used in cost–benefit analysis between countries. In this paper, we therefore examine how long transport infrastructure was used in the past before it was replaced, closed, or substantially improved. We label this period the ex-post appraisal period. The study considers rail and roads in Norway and analyses how long they were used using the statistical technique survival analysis. The results show that motorways build in the 1960s was used around 40 years before being upgraded, while most of railroad infrastructure have lasted more than 100 years. If these results are applicable for the future use it may indicate that the use of long appraisal periods (more than 50 years) in some countries could be optimistic for roads and rather conservative for railroads.