1. TNO Human Factors Mental load of the Westerschelde tunnel operator Drs. Jouke Rypkema TNO Human Factors P.O Box 23 3769 ZG Soesterberg +31 346 356322 rypkema@tm.tno.nl

2. Human Factors Mental load of the Westerschelde tunnel operator2 Westerschelde motor-traffic tunnel: location

3. Human Factors Mental load of the Westerschelde tunnel operator3 Westerschelde motor-traffic tunnel: details 6.6 km long 2 tubes, each tube 2 driving lanes Evacuation corridors every 250 m Cameras every 150 m 20 monitor displays Sensors (e.g. traffic speed, vehicle height, sight) Controllers (e.g. traffic lights, speed reduction signs) One operator to guard the tunnel

4. Human Factors Mental load of the Westerschelde tunnel operator4 Question: Can the tunnel be controlled safely by one tunnel operator?

5. Human Factors Mental load of the Westerschelde tunnel operator5 Cognitive load analysis Is the operator capable to (cognitively) perform his or her tasks?

6. Human Factors Mental load of the Westerschelde tunnel operator6 3D cognitive load model

7. Human Factors Mental load of the Westerschelde tunnel operator7 Scenarios Five scenarios were analysed Some severe (for example, accident with bus that catches fire) Some more common (for example, car without fuel standing still in tunnel)

8. Human Factors Mental load of the Westerschelde tunnel operator8 Scenarios: method analysis Event Bus hits car and catches fire, two lanes blocked procedure Perform calamity System (TUBES) OperatorTime 0 5 5 35 Notification (auditory/visual) Detection on MMI Autostart ventilation (after 60s) Press calamity button 1 5 30 0 Auto CCTV selection Build-up internal image

9. Human Factors Mental load of the Westerschelde tunnel operator9 Results Time occupied always high (vigilance) Overall, average cognitive load acceptable, but Cognitive load is extremely high for three scenarios during period just after incident Scenario 123 Time (in sec) 0 - 6750 - 11050 - 920 Time occupied (in %) 100 Complexity (in %) 525423 Task-set switches (number) 131210 Task-set switches (average time between switches) 5292 Critcal period

10. Human Factors Mental load of the Westerschelde tunnel operator10 Results (2) Level of information processing Task-set switches Time occupied 1 2 3 4 5 1 2 3

11. Human Factors Mental load of the Westerschelde tunnel operator11 Conclusions Cognitive load too high at the start of incidents, because: Too many tasks in short time (especially with evacuation) Tasks too complex because lack of (clear) procedures Sometimes number of task-set switches too high as a result of intertwined task-sets And: Sudden change from monotonous vigilance task to highly demanding crisis situation Responsibility until emergency services arrive

12. Human Factors Mental load of the Westerschelde tunnel operator12 Recommendations Develop / improve procedures related to categories of incidents. Develop evacuation procedures. Pay attention to communication and guidance. Improve procedures for communication with third parties. Restrict communication tasks during crisis situations. Cluster the operator tasks in sets. Provide a second person for assistance during crisis situations.

13. Human Factors Mental load of the Westerschelde tunnel operator13 Recommendations training Train “on the job” for normal situations. Use a simulator to train for critical situations. Repeat training frequently (3-6 monthly). Organize interdisciplinary training with emergency services.

14. Human Factors Mental load of the Westerschelde tunnel operator14 Thank you for your attention For more information contact: Jouke Rypkema rypkema@tm.tno.nl