"Overtaking" Project (2008 – present)
Name: Overtaking while driving
Type: Fundamental research
Funds: Doctoral fellowship (Contrat Doctoral, Ministère de l'Education Nationale de la Recherche et de Technologie), Lab's fund (Action Concertée Incitative, Institute of Movement Science Etienne-Jules Marey funds)
key researchers: Antoine MORICE, Numa BASILIO, Gilles MONTAGNE
Collaborators: Gabriel DIAZ, Brett J. FAJEN
The project :
Traditionally, perceptual processes leading to the selection of suited action mode can be studied through the affordance theory (Gibson, 1977, Warren, Jr., 1984; Warren, Jr. & Whang, 1987) whereas action should be regulated by “laws of control” (Warren, 1988). However, the “affordance-based control” framework (Fajen, 2007) challenge this view and suggests that affordances are perceived not only before the action, but also throughout it, to regulate action. We hypothesized that drivers could perceive possibilities for overtaking offered by the driving situation by perceiving an affordance for ‘passability’ and regulate their behavior accordingly. This ‘passability’ affordance could be embodied in the relationship between different action capabilities related to the vehicle driven (e.g., the Maximal Velocity VMAX and Maximal Acceleration AMAX of the car) and the kinematics constraints of the driving situation experienced (e.g., the Minimum Satisfying Velocity MSV and/or Acceleration for successful overtake MSA).
We use a fixed-base simulator (Mobsim, France) supporting spring-loaded pedals (Trackstar 6000 GTS, Extreme Competition Controls Inc., Minneapolis/Burnsville, MN, USA) and a steering wheel (Trackstar 6000 GTS, Extreme Competition Controls Inc., Minneapolis/Burnsville, MN, USA). From the USB signals of pedals and steering wheel, a custom-made virtual reality application (ICE software) running on a host computer PC compute on-line the virtual scene that is stereoscopically displayed at a frame rate of 75 Hz in a head-mounted display (Hi-res 900 stereo, Cybermind corp., Maastricht, The Netherlands). An integrated electromagnetic head tracking system (6 DoF Flock of Birds, Ascension Technology Corp., Milton, VT, USA) link the viewpoint in the virtual world with rotations of the head.
Past Experiments :
Experiment #1 : First definition f the overtaking ability affordance involving velocities
In the first experiment, we deﬁned the overtake-ability affordance as a ratio of the minimum satisfying velocity required for safe overtaking (MSV) to the maximum velocity of the driver’s car (Vmax). Two groups of participants performed overtaking maneuvers, if deemed possible, by driving either a slow (Vmax = 25 m/s) or a fast (Vmax = 32.5 m/s) virtual car in overtaking situations constrained by 14 values of MSV. As shown on the figure, for any given MSV condition, participants in the fast car group were more likely to attempt an overtaking maneuver. However, when MSV was expressed in intrinsic units as a ratio of Vmax for both groups, the frequency of overtaking was not signiﬁcantly different across groups. Furthermore, overtaking frequency dropped to near 0% for both groups when MSV exceeded Vmax. In accordance with the affordance-based framework (Fajen, 2007), our results suggest that participants select their 30 overtaking maneuvers by perceiving an overtake-ability affordance.
Experiment #2 : Second definition of the overtaking ability affordance including accelerations
In the second experiment, we defined the vertake-ability affordance as the ratio of the “minimum satisfying acceleration” (MSA) to the maximum acceleration of the driver's car (Amax). Two groups of nine drivers drove cars differing in their Amax. They were instructed to attempt overtaking maneuvers in 25 situations resulting from the combination of five MSA and five MSV values. We evidenced that when overtaking frequency was expressed as a function of MSV and MSA, maneuvers were found to be initiated differently for the two groups. However, when expressed as a function of MSV/Vmax and MSA/Amax, overtaking frequency was quite similar for both groups. Finally, a multiple regression coefficient analysis demonstrated that overtaking decisions are fully explained by a composite variable comprising MSA/Amax and the time required to reach MSV. Drivers were thus found to reliably decide whether overtaking is safe (or not) by using low- and high-order variables taking into account their car’s maximum velocity and acceleration, respectively, as predicted by “affordance-based control” theory.
Key references (downloadable version in page Publications)
- Morice, A.H.P., Diaz, G.J., Fajen, B.R., Basilio, N., Montagne, G. (2015) An affordance-based approach to visually guided overtaking, Ecological Psychology, 27(1), 1-25
- Basilio N., Morice, A.H.P., Marti, G., Montagne, G. (2015) High and low order overtaking-ability affordances: Drivers rely on the maximum velocity and acceleration of their cars to perform overtaking maneuvers. Human Factors: The Journal of the Human Factors and Ergonomics Society,57 (5), 879-894