OSSOKINA

Highway widenings lead to less congestion during at least 6 years | The Netherlands



Highway construction occurs nowadays mainly through widening of existing roads rather than building new roads. This paper documents that highway widenings considerably reduce congestion in the short run, defined here as 6 years. Using big data (high frequency observations) from detectors located in the Dutch highway network, we find substantial travel time savings after widenings. These savings occur despite strong increases in traffic flow. The welfare benefits in the short run already cover 40% of the widenings' investment costs. Our paper contributes to an explanation why countries invest in roadworks even when the fundamental law of congestion predicts that travel savings disappear in the long run.

The above figure shows the importance of highway widenings for the policy. The total length of the highway network in the Netherlands grew with a factor 3 between 1960 and 1990 but did not increase substantially since. In contrast, the number of lanes – and thus the number of lane kilometres - kept steadily rising and is going to increase further in the coming years.


November 2022


Publications:

- Ossokina, I.V., Van Ommeren, J and H. van Mourik (2022) Do highway widenings reduce congestion?,, Article forthcoming in Journal of Economic Geography