Publication type: Conference paper
Type of review: Peer review (publication)
Title: Speed and lane dependent net time headway distributions on freeways : comparing empirical and simulated data
Authors: Steiner, Albert
Leonhardt, Axel
Proceedings: TRB 93rd Annual Meeting Compendium of Papers
Pages: 1
Pages to: 17
Conference details: 93rd Annual Meeting of the Transportation Research Board, Washington, USA, 12-16 January 2014
Issue Date: 2014
Publisher / Ed. Institution: Transportation Research Board
Publisher / Ed. Institution: Washington
Language: English
Subjects: TRB; Traffic; Model estimation; Simulation
Subject (DDC): 
Abstract: An important variable to characterize freeway traffic flow is the net time headway. In this paper empirical net time headway distributions with respect to four different speed classes as well as the right and left lane were analyzed. As passenger cars represented the vast majority of the vehicles, only pairs of passenger cars (leader/follower) were considered. It could be shown that the net time headway distributions strongly depend on the traffic lane and the speed class. To estimate the corresponding probability density functions (pdf), the gamma-Generalized-Queuing-Model was used and model parameters were estimated by applying a non-linear least squares approach. The microscopic traffic simulation tool PTV VISSIM was used to address the main objective of this study, namely to determine if and to what extend the empirical distributions of the net time headways can be met by simulations. To achieve this goal, the number of vehicle classes required together with specific parameter settings was investigated, whereby again the pdf and its parameters were estimated for each simulation scenario. It could be shown that substantial improvements regarding the reduction of the deviations between simulated and empirical headway distributions can be achieved by adding vehicle classes for passenger cars to account for a relatively wide distribution of observed empirical net time headways. Additional findings were related to the sensitivity of the parameters of the microscopic model as well as those of the density functions. Potential future research includes, amongst others, extended parameter studies and applying the methodology to other car following models.
URI: https://digitalcollection.zhaw.ch/handle/11475/13636
Fulltext version: Published version
License (according to publishing contract): Licence according to publishing contract
Departement: School of Engineering
Organisational Unit: Institute of Data Analysis and Process Design (IDP)
Appears in collections:Publikationen School of Engineering

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