Abstract
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.
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 language | English |
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Title of host publication | Traffic and granular flow 2007 |
Editors | C Appert-Rolland, F Chevoir, P Gondret, S Lassarre, JP Lebacque, M Schreckenberg |
Place of Publication | Heidelberg |
Publisher | Springer |
Pages | 351-356 |
Number of pages | 6 |
ISBN (Print) | 978-3-540-77073-2 |
DOIs | |
Publication status | Published - 2009 |
Event | Traffic and Granular Flow '07, Orsay, France - Heidelberg Duration: 20 Jun 2007 → 22 Jun 2007 |
Publication series
Name | |
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Publisher | Springer |
Conference
Conference | Traffic and Granular Flow '07, Orsay, France |
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Period | 20/06/07 → 22/06/07 |
Keywords
- Conf.proc. > 3 pag