The highway A4 in the Netherlands was extended with an additional part between Delft and Schiedam. The Dutch newspaper NRC used the real-time traffic data that is available as Open Data to assess the impact of the opening of the new highway. Data such as the number of cars and average speed on the A13 highway was therefore estimated as well as the expected benefits from the road works.
It turns out that a lot of people tried the new road after it just opened, but choose their normal route again shortly after. Still, the amount of traffic on the A13 decreased significantly. This means that the opening of the new highway has the desired effect on avoiding long traffic jams during rush hours.
Do you want to discover more details? Different visualisations and graphs are included in the article.
Read more (in Dutch): http://www.nrc.nl/nieuws/2016/02/03/wat-is-het-effect-van-de-a4