Evaluation of Roundabout Designs using Driving Simulation

Abstract

A strong focus on traffic safety and an increasing number of cyclists in Norway, have caused a shift towards more continental roundabouts to be considered in order to lowering vehicle speeds at roundabouts. The objective of this thesis is therefore to evaluate how entry speed changes with continental roundabouts.

A literature review has been conducted to get a better understanding of what a Continental roundabout is and what effects they have, as well as to investigate existing studies.

Furthermore, this research includes a simulator study developed in order to investigate how entry speed and heading change when converting to more Continental roundabout designs in a Norwegian context. A total of four roundabouts with different entry designs has been modelled and tested in a low-level simulator. The first roundabout is a tangential roundabout, designed in accordance with the Norwegian roundabout design guidelines, while the other three are various Versions of a continental roundabout. Entry speeds and heading from 20 test participants (13 males and 7 females) were then recorded and compared between the reference design and the three alternative designs.

Results from three paired samples t-tests shows that the mean entry speed is significantly reduced at the roundabouts that comply with a continental design compared to the Reference design. Furthermore, data recorded on speed and heading at entry are not found to be significantly correlated. Results indicate that entry path curvature has a larger effect on entry speed than entry angle. This coincides with the findings of no correlation between speed and heading.