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