Scenarios
Wiebo H. Brouwer
S09-LGI-UGRON

The test consists of driving on a winding country road with traffic from the opposing direction only. The main task is to drive to drive safely in the middle of the right lane.

• The first part, where speed is controlled by the computer, consists of six 700 m sections. The first section is driven at 50 km/h and increasing to 100 km/h in steps of 10 km/h.
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• In the second part the driver controls speed. Usually this test is done in an automatic transmission mode. For the first 2100 m, the task is to drive at a comfortable speed while in the last 2100 m the task is to drive as fast as possible while still driving safely (as if in a hurry).

For all conditions the average lateral position, the standard deviation of lateral postion, lane crossings left and right and collisions with other traffic are computed and compared in an Excel file with results from healthy control subjects and relevant patient groups.

The city ride is developed by Ragnhild Davidse and Peter van Wolffelaar in the framework of a study on the use of ITS in healthy older drivers. It comprises city and suburb driving in a situation with many intersections and interactions with other traffic. It was already applied in over 50 healthy older subjects (50-89 years) in the framework of Ragnhild's study on the effects of ITS in healthy older persons.

Speed, lateral position and state of winking indicator, accelerator (in automatic transmission mode; else also gear lever and clutch pedal) and brakes are continuously assessed. For some intersections attention and reaction time on a peripheral detection task are collected.

For every intersection, dependent on the manoeuvre (turning right, turning left, straight ahead, crossing) the following actions of the car are recorded:

• Lateral position in case of stop before intersection
• Distance to centre of intersection in case of stop
• Distance of first car from left to centre of intersection when subject drives off
• Distance of first car from right to centre of intersection when subject drives off
• Driving speed car left when subject drives off
• Driving speed car right when subject drives off
• Time Head Way (THW) left when subject drives off (the gap between traffic from the left side that the subject chooses)
• THW right when subject drives off (gap between traffic from right side)
• Time To Intersection (TTI) left when subject drives off (in how many s is the car from left on the intersection)
• TTI right when subject drives off (as above for car from the right side)
• Acceleration of Deceleration of traffic from left when subject drives off (must car from the left brake because of subject's action)
• Acceleration or deceleration of traffic from right when subject drives off
• Clock time when subject drives off (for synchronizing with default video-recording of test ride and driver's head)
• Remaining following distance of car from right/left after turning (if subject has turned then what is the following distance of the car before which he has merged?)
• Post Encroachment Time (PET) to car from right after crossing (time between subject passing centre of intersection and crossing car doing so.
• Acceleration or deceleration of car from right after crossing (does the new follower brake because of the subjects' merging?)
• Acceleration of subject after crossing/turning (does the subject accelerate fast?)
• Driving speed subject after crossing/turning
  

At this moment, performance of the city ride is only assessed in a qualitative manner according to the TRIP protocol awaiting validation and norming the abovementioned quantitative measures.

Coming soon!