Abstract
Road trains has been used internationally in many years, but it was first in 2008 the first trials with road trains (up to a length of 25.25m) on the Danish road network were initiated. The trial period was extended several times and is now prolonged to 2030, i.e. virtually as a permanent arrangement.
The state roads and selected municipal roads have ongoing been rebuild to ensure sufficient space for these road trains – design changes, which mainly have been concentrated in nodes. In total are around 150 locations, of which a considerable part are roundabouts, converted to ensure passage. In single lane roundabouts the central island is reduced and the area added to the lane.
All things being equal, it allows especially private cars to increase the speed in the roundabouts, as the turning radius will be bigger with an increasing width of the lane. The hypothesis is that the redesign will increase the speed through the roundabout considerably.
This study consists of two sub studies; a before/after study in one round about and a with/without study in two identical roundabouts with exception of the increased width of the lane in one of the roundabouts. In common for the studied roundabouts are a moderate traffic level (AADT of 6-8,000) and outside built up areas.
For each roundabout one week of video registration before and one after the redesign of it were recorded. Similarly, one week of data was recorded in the roundabout with and without the increased lane width, respectively.
Based on the measured time use between two location identified in the roundabout for private cars driving under free flow conditions, an estimation of the speed with/after compared to the speed without/before the redesign is made for in total 100 cars per week per location.
The very first tentative results show that the speed increases from about 28 kph to nearly 38 kph. It is therefore plausible that it resulted in increased accident risk and additionally increased speed variation, which is normally an outcome of an increased speed level.
The final results will be presented in the final paper.
The state roads and selected municipal roads have ongoing been rebuild to ensure sufficient space for these road trains – design changes, which mainly have been concentrated in nodes. In total are around 150 locations, of which a considerable part are roundabouts, converted to ensure passage. In single lane roundabouts the central island is reduced and the area added to the lane.
All things being equal, it allows especially private cars to increase the speed in the roundabouts, as the turning radius will be bigger with an increasing width of the lane. The hypothesis is that the redesign will increase the speed through the roundabout considerably.
This study consists of two sub studies; a before/after study in one round about and a with/without study in two identical roundabouts with exception of the increased width of the lane in one of the roundabouts. In common for the studied roundabouts are a moderate traffic level (AADT of 6-8,000) and outside built up areas.
For each roundabout one week of video registration before and one after the redesign of it were recorded. Similarly, one week of data was recorded in the roundabout with and without the increased lane width, respectively.
Based on the measured time use between two location identified in the roundabout for private cars driving under free flow conditions, an estimation of the speed with/after compared to the speed without/before the redesign is made for in total 100 cars per week per location.
The very first tentative results show that the speed increases from about 28 kph to nearly 38 kph. It is therefore plausible that it resulted in increased accident risk and additionally increased speed variation, which is normally an outcome of an increased speed level.
The final results will be presented in the final paper.
| Original language | English |
|---|---|
| Title of host publication | 29th ICTCT Workshop in Lund, Sweden on 20th and 21st October 2016 : How to assess traffic safety? - Adapting methods to future challenges - Book of abstracts |
| Number of pages | 1 |
| Place of Publication | Lund |
| Publisher | International Co-operation on Theories and Concepts in Traffic Safety (ICTCT) |
| Publication date | 2016 |
| Pages | 51 |
| Publication status | Published - 2016 |
| Event | 29th International Co-operation on Theories and Concepts in Traffic Safety (ICTCT Workshop): How to assess traffic safety? - Adapting methods to future challenges - Lund University, Department of Technology and Society, Division of Traffic Engineering, Sweden, Lund, Sweden Duration: 20 Oct 2016 → 21 Oct 2016 Conference number: 29 |
Conference
| Conference | 29th International Co-operation on Theories and Concepts in Traffic Safety (ICTCT Workshop) |
|---|---|
| Number | 29 |
| Location | Lund University, Department of Technology and Society, Division of Traffic Engineering, Sweden |
| Country/Territory | Sweden |
| City | Lund |
| Period | 20/10/2016 → 21/10/2016 |
Keywords
- Road trains
- Roundabouts
- Speed
- Redesign
- Lane width