Contents
The Sétra supports the public owner ............................................................................ 2
The Sétra, producer of the state of the art.................................................................... 2
The Sétra, a work in partnership .................................................................................. 2
Contents..................................................................................................................... 5
1 - Overview .............................................................................................................. 7
1.1 – Context .......................................................................................................... 7
1.2 – Problem statement ......................................................................................... 7
1.2.1 – Roundabout creation ........................................................................................ 9
1.2.2 – Development of existing junction into roundabout........................................... 9
1.2.3 – Existing roundabout ......................................................................................... 9
1.3 – Data inventory ............................................................................................. 10
1.4 – Proposed approach....................................................................................... 10
2 - Risk analysis ...................................................................................................... 11
2.1 – Risks ............................................................................................................ 11
2.1.1 – Risk of road accident ...................................................................................... 11
2.1.2 – Risk of accident on level crossing .................................................................. 11
2.1.3 – Scenario in which a risk assessment is required ............................................ 13
2.2 – Risk assessment ........................................................................................... 14
2.2.1 – Data compilation ............................................................................................ 14
2.2.2 – Preparation procedure ................................................................................... 14
2.2.3 - Queue calculation ........................................................................................... 14
2.2.4 - Risk assessment ............................................................................................... 14
3 - Solution proposal .............................................................................................. 16
3.1 – Preventive measures .................................................................................... 16
3.1.1 – Increase in static signing (P1)........................................................................ 16
3.1.2 – Addition of dynamic signing (P2)................................................................... 17
3.1.3 – Level crossing entry light management (P3) .................................................. 18
3.2 – Corrective measures .................................................................................... 19
3.2.1 – Clearance area creation (C1a) ...................................................................... 19
3.2.2 – Direct right-turning lane (C1b)...................................................................... 19
3.2.3 – Management of lights (R22j) at one or more roundabout entrances (C2) ..... 19
3.2.3 – R22v slight signal management on roundabout ring (C3) ............................. 21
4. Specific scenarios................................................................................................ 22
4.1 – Roundabout very close to level crossing ..................................................... 22
4.2 – Mini-roundabout.......................................................................................... 22
4.3 – Level crossing inside roundabout ................................................................ 22
4.4 – Summary table of proposed solutions ......................................................... 23
Appendix 1 - Level crossing clearance time calculation [1] ............................... 25
Appendix 2 - Detections ......................................................................................... 26
Downstream queue ............................................................................................... 26
Vehicle stopped on level crossing ........................................................................ 26
Traffic upstream from level crossing ................................................................... 26
Traffic upstream from the entrance N-1 ............................................................... 26
Appendix 3 - Bibliographic references ................................................................. 27
Appendix 4 - Glossary of terms............................................................................. 28
