IATSS Review
Online ISSN : 2433-4537
Print ISSN : 0386-1104
Effects of Raising the Maximum Speed on a High-Standard Expressway
Nobuhiro YANOToshiya YOKOZEKIKenji MORI
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2021 Volume 45 Issue 3 Pages 190-197


The maximum speed of certain sections of expressway were raised above 100km/h on a trial basis starting in November 2017. This paper reports the results of a study case that examines the impact this increase in the maximum speed had on traffic conditions. This study looked at the effect that the increase in the speed limit to 110km/h and 120km/h had from three different perspectives – changes in the travel speed, changes in the frequency of lane changes, and changes in the risk of collision when overtaking based on the margin-to-collision index. Although the data collected through to March 2019 did not show any significant effect of raising the maximum speed limit, some interesting changes were brought to light. The effects of raising the maximum speed limit will require further observation over a longer time span in the future.

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© 2021 International Association of Traffic and Safety Sciences
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