Roundabout Installation

Main Roads Western Australia engaged GHD for data on a project for the Urban Road Safety Program. They wanted to compare driver behaviour before and after the installation as well as introduce low-cost road safety treatments which, in this case, are painted roundabouts.

The roundabouts were added to reduce driver speeds through the intersections and between intersections. This is to reduce near-miss incidents.

MRWA determined the effectiveness of these 4 roundabouts by analysing:

• Average speeds,
• Vehicle turning movements
• Average braking (g-forces) and
• Comparing the above statistics in the time before and after the installation.

The results showed that the painted roundabouts were equally effective in reducing driver speeds compared to a raised roundabout. The intersections were operating more safely and efficiently with average speeds dropping to 50km/h. This also shows future crashes are less likely to have a serious outcome or injury.

The painted roundabouts were proven to manage speeds below safe systems thresholds.

By using connected vehicle data, MRWA and GHD were able to obtain data that couldn’t be achieved by strips or road loops. Installation was impossible at the conflict points because they were in the middle of the intersections. The data managed to show driver behaviour as they travelled through the intersection, measuring data at the conflict point. The loops an also impacct driving behaviour and recorded data.