Empirical differences between time mean speed and space mean speed

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientific

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Insight into traffic flow characteristics is often gained using local measurements. To determine macroscopic flow characteristics, time aggregation of microscopic information is required.

Usually, a data collection system stores values averaged over time. However, it is well known that a time mean average overestimates the influence of faster vehicles, and consequently overestimates the mean speed. As a direct result, densities, computed from flow and speed, are underestimated.

This paper compares the time mean speed and space mean speed, using data of individual car passages on a motorway road stretch. We show that the differences between time mean and space mean averages are substantial, up to a factor four. In particular in the lower speed regions the error is big. We indicate the considerable consequences for the jam density and shock wave speed. Finally, a fundamental diagram based on correctly averaged microscopic data can be fitted much better.
Original languageEnglish
Title of host publicationTraffic and granular flow 2007
EditorsC Appert-Rolland, F Chevoir, P Gondret, S Lassarre, JP Lebacque, M Schreckenberg
Place of PublicationHeidelberg
Number of pages6
ISBN (Print)978-3-540-77073-2
Publication statusPublished - 2009
EventTraffic and Granular Flow '07, Orsay, France - Heidelberg
Duration: 20 Jun 200722 Jun 2007

Publication series



ConferenceTraffic and Granular Flow '07, Orsay, France


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    Knoop, VL., Hoogendoorn, SP., & van Zuylen, HJ. (2009). Empirical differences between time mean speed and space mean speed. In C. Appert-Rolland, F. Chevoir, P. Gondret, S. Lassarre, JP. Lebacque, & M. Schreckenberg (Eds.), Traffic and granular flow 2007 (pp. 351-356). Springer. https://doi.org/10.1007/978-3-540-77074-9_36