(5) INTERACTION Final event - Speed regulation systems Effects
1. Understanding driver interactions
with In-Vehicle Technologies
Behaviour Observations
Clemens Kaufmann (FACTUM)
Ralf Risser (FACTUM)
INTERACTION Final Event
22 November 2012, Brussels
2. Behaviour observations – Wiener Fahrprobe
• Each test persons observed twice
(with/without system active)
• Two observers with different tasks
– Coding observer
– Free observer
• Results from both observers
3. Sample Cruise Control
Country CC
Czech Republic 15
Finland 15
France 15
The Netherlands
Portugal 8
Spain 9
UK 15
Total (N) 77
4. Cruise Control
• Used on highways
• Speed selection variables
– According to the limits
– Higher than the limits (up to 30km/h higher)
– Lower than the limits (according to the traffic
situation)
– Hardly/never changed vs. speed changed
quite often
5. Results Cruise Control
• No differences between the rides with and
without activated CC regarding:
– Longitudinal control
– Lateral control
– Obeying traffic rules
– Interaction with other road user
– Antcipation
• Significantly less driving too fast with CC
6. Problems with Cruise Control
• Problems with CC
– Too fast according to the limits and situations
– Approaching other cars without changing the speed
– Overtaking manouvers
Takes long time to overtake other cars
Abort overtaking manouver
Driving too close to the car in front
Overtaking on the right side
• Conflicts only observed on the rides with an
active CC
7. Conclusion Cruise Control
• CC helps keeping the speed
• but does not prevent from driving too fast
• Problems in situation when speed has to
be adapted
– Overtaking manouvers
– Slower car in front
– Exiting the highway
• Inexperienced users claimed to have
problems (functions & interface)
8. Sample Speed Limiter
Country SL
Czech Republic
Finland
France 15
The Netherlands
Portugal 8
Spain 9
UK
Total (N) 32
9. Issues related to Speed
• Used on rural roads and urban areas
• Speed selection in the system
– Mostly according to the limits
– Higher than the limits (up to 30km/h)
– Lower than the limits (20 km/h lower)
– Speed was changed as soon as the speed limit
changed
– Speed was set in the beginning and never changed
– Using two speeds – one for rural roads one for
urban areas
10. Results Speed Limiter
• No differences between the rides with
and without an activated SL regarding
– Speed behaviour
– Longitudinal control
– Lateral control
– Obeying traffic rules
– Interaction with other road user
– Antcipation
11. Problems with Speed Limiter
• Problems while using SL
– Not recognising the change of the
speed limit
– Distraction while setting speed
– Misinterpreting signals
• Conflicts (right-angle, rear-end,
vulnerable road user) more often
observed while using the system
12. Conclusion Speed Limiter
• SL helps keeping the speed
• but does not prevent from driving too fast
• Problems in situations
– When speed limit changes
– Handling with the system
– System is not well known
13. Sample Speed Alert
Country SA
Czech Republic
Finland
France
The Netherlands 20
Portugal
Spain
UK 15
Total (N) 35
14. Use of Speed Alert
• Used on rural roads and in urban areas
• SA function of the NS was used
• Most of the times speed was immediately
reduced after warning
15. Results Speed Alert
• No differences between the rides with and
without an activated SA regarding
– Speed behaviour
– Lateral control
– Obeying traffic rules
– Antcipation
• Significantly more often too close to the car in
front
• Significantly more erros in the communication
behaviour
16. Problems with Speed Alert
• Problems while using SA
– No major differences in the driving behaviour
– More often shorter distances to the car in front
– More errors in the interaction with other road users
(indicating behaviour, against vulnerable road
users)
– Similar conflict (right-angle, head-on) situations with
and without the system
17. Conclusion Speed Alert
• Especially problems with distance
keeping and interaction
• Observers found it difficult to ascribe
differences in the behaviour to the use of
the SA
18. Advantages and Problems of
Speed Regulating Systems
• Advantages
– Systems help the test persons to keep the speed
– No major influence on the driving behaviour
• Problems
– In specific situations when speeds has to be adapted
– Handling with the system (especially when system is
new)
– Systems are used in a not wished for way
