Regensburg 2004 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
AKSOE: Physik sozio-ökonomischer Systeme
AKSOE 2: Urbane Systeme und Verkehrsdynamik
AKSOE 2.1: Talk
Monday, March 8, 2004, 14:00–14:30, H8
New experimental results concerning the car-following dynamics — •Peter Wagner1, Georg Hertkorn1, and Ihor Lubashevsky2 — 1Institut für Verkehrsforschung, Deutsches Zentrum für Luft- und Raumfahrt, Rutherfordstrasse 2, 12489 Berlin — 2General Physics Institute, Russian Academy of Sciences, Vavilov Str. 38, Moscow, 119991, RUSSIA
Car-following experiments conducted recently with cars equipped with DGPS (differential GPS) deliver fairly accurate and highly interesting data. The distances Δ x, the speeds v(t) and the accelerations can be measured (or computed) making it possible to draw solid conclusion related to the car-following dynamic.
In contrast to almost all of the car-following models currently in use the data demonstrate that the behaviour of the drivers is described by fairly old (but rarely used) ”action-point” models. These models claim that the acceleration is constant most of the time but is changing very fast at the action-points. The time between subsequent action-points is distributed exponentially, compatible with the assumption that the decision to change acceleration is drawn randomly.
It follows, that there is no fixed-point of the car-following dynamic. It can be hypothesized that this is due to driver’s inability to regulate speed difference Δ v and acceleration exactly to zero. Nevertheless, there is a strong attraction toward these values, as can be seen by the cusp in the frequency distribution of Δ v=0.
From these results, important consequences might be drawn for the modeling of the car-following process.