0000000001077280
AUTHOR
Sandro Chiappone
Traffic simulation models calibration using speed–density relationship: An automated procedure based on genetic algorithm
Calibration of traffic models.Calibration as optimization problem.Use of genetic algorithm. This paper presents the first results of a research which applied a genetic algorithm to calibrate a microscopic traffic simulation model based on speed-density relationships. A large set of traffic data collected from the A22 Freeway, Italy, was used and a comparison was performed between the field measurements and the simulation outputs obtained for a test freeway segment by using the Aimsun microscopic simulator.The calibration was formulated as an optimization problem to be solved based on a genetic algorithm; the objective function was defined in order to minimize the differences between the sim…
Analisi di rilievi NRTK condotti con differenti reti di stazioni permanenti in Sicilia
In questo studio, tuttora in corso di approfondimento e di investigazione, viene svolta un’analisi comparata sulle correzioni differenziali ottenute da reti di stazioni permanenti differenti, ma operanti sullo stesso territorio, quello siciliano. Infatti dopo la rapida diffusione delle tecnologie informatiche, in Sicilia negli ultimi anni, si è assistito ad una proliferazione di stazioni permanenti GPS, da parte di enti pubblici e società private. In particolare nel territorio regionale siciliano sono presenti ben cinque reti di stazioni con differenti ubicazioni, strumentazioni utilizzate, software di gestione e sistemi di riferimento geodetico; oltre quella gestita e coordinata dalla Faco…
Calibration of Speed-Density Relationships for Freeways in Aimsun
The first application of a calibration methodology which uses speed-density relationships in the microsimulation calibration process is described in this article. Traffic patterns were implemented developing speed-density relationships for empirical and simulated data. For empirical relationships reference was made to traffic data observed at A22 Freeway (Italy). Aimsun microscopic traffic simulator software was then used to obtain analogous relationships for a test freeway segment under uncongested traffic conditions. Thus on field conditions were reproduced varying some calibration parameters until a good matching between field and simulation was achieved. The closeness between empirical …
A microsimulation calibration methodology based on speed-density relationships for freeways
This paper describes the calibration methodology based on speed-density relationships in the microsimulation calibration process, stated that they represent the traffic flow phenomenon in a wide range of operational conditions and well summarize all the information that may be collected on field (or following a run of the microsimulation model) on two of the three key variables of traffic flow. The matching of speed-density relationships from field and simulation was evaluated using statistical analysis as technique of pattern recognition. A test freeway segment under uncongested traffic conditions was selected as case study; based on traffic data observed at A22 Brenner Freeway, Italy, sta…
Developing Passenger Car Equivalents for Freeways by Microsimulation
Abstract In this paper a method of estimation of the passenger car equivalents for heavy vehicles on freeway is described. The variation in traffic quality was evaluated basing on a traffic demand characterized by different percentages of heavy vehicles. Aimsun micro-simulator was used to isolate traffic conditions difficult to capture on field, to replicate them to have a number of data as much as possible numerous, and to quantify the fundamental variables of traffic flow, namely the speed, flow, density, for a test freeway segment. Model calibration was accomplished by using traffic data collected at observation sections on the A22 Brenner Freeway, Italy. In order to check to what extent…