Yun-Pang Flötteröd

Identifiability and Practical Relevance of Complex Car-Following Models

This article looks at car-following models from a deliberately pragmatic perspective: What information about driver behavior can be extracted from a given data set without more or less speculative assumptions about underlying behavioral laws? The objective of this exercise is not to invalidate existing models but to obtain a better understanding of how much (complex) model structure can be revealed/validated from real data.

Simulation-based validity analysis of ecological user equilibrium

Traffic is believed to organize itself by minimizing users travel cost (travel time is used as cost very often). Almost all the analytical and numerical work in the last 50 years has concentrated on travel cost and the assumption that costs are always an increasing function of demand. With fuel consumption, this is no longer true, since there is typically an optimum speed where fuel consumption and emission production is minimized. This paper explores some of the implications when using fuel consumption as an objective function for achieving an user equilibrium traffic state. It turns out, that this leads to multiple solutions (multiple equilibriums) and sometimes counter-intuitive behavior, which makes it unlikely that such a scheme that minimizes fuel consumption alone will ever be implemented in real systems.