Selbstinduzierte Geschwindigkeitsoszillationin der Fahrzeugführung

This work is concerned with self-induced speed oscillations when driving a car. Although the driver is largely unaware of these variations, speed oscillates around a desired mean speed similarly a sine curve. While speed oscillations are often determined by the traffic situation (e.g. by a decelerating and accelerating vehicle in front of the driver), the present work focuses on „self-induced“ oscillations of the driver on a free straight road. The self induced speed oscillation is a phenomenon, which was not considered so far in the traffic-psychological research. In traffic flow models, which are a domain of the engineer research, the phenomenon is well-known, but is considered as unsystematical human error. A goal of this work is it to prove in contrast systematic influences on the self induced speed variation. Starting point of this work were salient differences in the speed process during rides of test persons in a driving simulator on nebula condition and on clear sigth: During nebula the test persons showed a more frequent speed variation than during clear sigth. To parameterize these differences a procedure was developed, which describes the speed oscillation on the basis of its extent („amplitude“) and its temporal duration („period“). The amplitude reflects the extent of the speed difference in km/h from a minimum in the sinusoidal variation of speed to the following maximum or vice versa. The period is the time, which passes between these two points. It was shown that the period varies strongly between the driving conditions (9-18 seconds) and becomes clearly smaller in fog (9-12 seconds). The amplitude of the speed oscillation remains the same over all conditions and is about 5 km/h. These new values were supplemented into a traffic flow model, which thereupon could point out the emergence of mass accidents during fog on motorways: The more frequent speed variation during fog leads in connection with the reduced foresight to stronger de- and acceleration procedures in vehicle chains, which are more often formed in the fog. The accidents then result from single drivers, who drive too fast in the fog, to be able to stop in their range of vision and then encounter the end of one of those strongly retarding vehicle chain. Here the meaning of the self induced speed variation shows up in connection with other driving parameters. In a further driving simulator investigation also the accelerator variation was examined. This illustrates directly human behavior, while the speed output is along-moderated by physical variables like the mass of the vehicle. It showed up that during nebula and at low speeds more time is spent in the regulation process, based on existing accelerator regulation in relation to phases of non-regulation, than while driving at clear sight or higher speed. In a further driving simulator experiment the reason for the differences in the self induced speed oscillation should be clarified. During a diverson of the attention from the driving task the closed loop of motor action control (consisting of alternating visual and motor control) should be less frequently, which leads to larger periods, since controls and regularization take place now more rarely. In the simulator experiment the attention of the test persons was diverted by sidetasks. Here the expected increase of the period of the speed oscillation showed up with a visual distraction (reaction on targets presented on a display in the center console), but not with a purely mental, acoustically presented distraction (reaction on target words in an audiobook). In a further condition the attention of the test person was directed on the front vehicle driving with constant speed (reaction on brief color change of the front vehicle). This simulates contentwise a ride on nebula condition, where drivers concentrate strengthened on the front vehicle. Here the expected shortening of the period showed up, which proves that the closed loop of motor action control will run faster in these situations. The work could prove that the self induced speed oscillation has systematic portions, which vary with the driving conditions contrary to the earlier findings. Further note for a personstable factor of the speed oscillation was found, interacting with the situation-specific factors. Characteristic values were formed and supplied results, which can be integrated into traffic flow models to the improve the forecast quality. The causes of speed oscillation could be assigned thereby to a theoretical model. The analysis of selfinduced speed oscillation can help to understand driving in common better – especially in the interaction of several vehicles – and offers an addition to the usually reported average values of speed.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2009

Author dc:creator

• Wille, Matthias

Contributors dc:contributor

• Debus, Günter

• info:eu-repo/classification/ddc/150
• Verkehrspsychologie
• Fahrerverhalten
• Aufmerksamkeit
• Geschwindigkeit
• Psychologie
• Geschwindigkeitsvariation
• Fahrzeugführung
• trafficpsychology
• driving
• speed
• oscillation
• attention

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113613%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A51307