Traffic simulation

About: Traffic simulation is a research topic. Over the lifetime, 6211 publications have been published within this topic receiving 95004 citations.

Some Aspects of a Switching Policy for Commuter Flow

Abstract: A wide range of signal switching policies may be adopted for control of traffic flow between a pair of intersections. One of the most important traffic situations is that in which rush-hour commuter traffic travels towards or away from a city center along radial roads. Under these circumstances opposing and tangential flow may be light. Earlier papers have shown that a modified form of the Dunne-Potts switching policy might be applied to pairs of intersections carrying commuter flow. Efficient and flexible operation of the system under a wide variety of flow conditions, and with the minimum of computer surveillance, was demonstrated. The present paper reports the results of further simulation experiments and discussed tentative solutions of some of the practical problems associated with the proposed scheme.

Vehicle classification in traffic models

Abstract: For traffic simulation it is necessary to know a lot of parameters. One of these is the vehicle classification. In order to be able to model a certain situation the composition of the traffic needs to be known to create a well-functioning model. There are a lot of different types and sizes of vehicles on the road, which makes it necessary for traffic simulation software to distinguish different vehicle types. The first step for determining the correct vehicle type is by collecting the data in the first place. In the Netherlands there is a public database for traffic on most national roads, the NDW. The data that is shared by them is already classified in three or five different classifications. Whether it is three or five categories depends on the accuracy of the measurement with higher accuracy measurements being represented by the five classifications system. For urban roads the NDW does not provide that much information, but this problem is sorted by companies like Sweco performing the needed traffic measurements themselves. Sweco also uses a classification system, but that has 13 vehicle classifications. To get the optimal representation of reality by a model it is ideal that individual vehicle data is available so that the traffic simulation software can have a tailor-made vehicle classification. Most of the vehicles are easy to determine a fitting vehicle category for in traffic simulation software. However, especially vans are a problematic vehicle category, because of the fact that they fall somewhat in between passenger cars and trucks, which are the most common vehicle categories in traffic simulation software. To determine the influence of the vehicle classification on the capacity of a road network some simulations are run. Because urban traffic is much different from highway traffic both of these two situations are considered. The highway situation is represented by an on-ramp on a highway and the urban situation by a signalled intersection. Three of the most used traffic simulation programs used by Sweco are used to determine the effect of vehicle classification on the capacity. Fosim and Vissim are used for the highway situation and Vissim and Paramics are used for the urban situation. Not only is there looked at the maximum capacity of these situations for multiple factors of freight traffic, but also the passenger car equivalent values for the capacity is considered. All the results show a linear correlation in the decrease of the capacity when there is an increase in the freight traffic factor. For the highways this is a decrease of around 70 vehicles per hour per percent and for the urban situation this is only around 5 vehicles per hour per percent less. The PCE-values for the highways also show a slight decrease in capacity, but only by around 20 vehicles per hour per percent less. However, the PCE-values for the capacity of the urban situation show an increase in capacity for additional freight traffic with an increase of around 3 vehicles per hour per percent freight traffic. If the PCE-values would remain the same for each freight traffic factor it does not matter in which category vans are placed. However, because this is not the case there are slight changes in capacity possible for classifying vans in a different category. These changes are up to two percent for highways and up to three percent for the urban situation when it is known that vans make up almost seven percent of all Dutch vehicles.

Towards data-driven microscopic traffic simulation models

Abstract: Στόχος της έρευνας είναι η ανάπτυξη πιο αξιόπιστων μικροσκοπικών κυκλοφοριακών προτύπων. Αναπτύσσεται μια ολοκληρωμένη μεθοδολογία για την εκτίμηση προτύπων κυκλοφοριακής προσομοίωσης με τη χρήση καινοτόμων και ευέλικτων μεθόδων μηχανικής μάθησης, όπως η ταξινόμηση, η ομαδοποίηση, η τοπικά σταθμισμένη παλινδρόμηση (loess), οι καμπύλες splines, οι Gaussian διαδικασίες, οι διανυσματικές μηχανές υποστήριξης και τα νευρωνικά δίκτυα. Τα δεδομένα που χρησιμοποιήθηκαν στην έρευνα αυτή περιλαμβάνουν δεδομένα από τρεις διαφορετικές πηγές, δεδομένα από τη Νάπολη, τα NGSIM δεδομένα και δεδομένα από την Ινδία. Δίνεται έμφαση στα πρότυπα ακολουθίας οχημάτων και για τα ίδια δεδομένα εφαρμόζεται το μοντέλο του Gipps, ένα γνωστό μοντέλο ακολουθίας οχημάτων που χρησιμοποιείται ως μοντέλο αναφοράς στην παρούσα έρευνα. Επειδή πολλοί παράγοντες επηρεάζουν τη συμπεριφορά του οδηγού, εξετάζεται κατά πόσο βελτιώνεται το μοντέλο ενσωματώνοντας περισσότερες μεταβλητές. Επιπλέον, εξετάζεται η δυναμική βαθμονόμηση κυκλοφοριακών προτύπων λαμβάνοντας υπόψη τη δυναμική μεταβολή των παραμέτρων για κάθε οδηγό, στον χρόνο και το χώρο. Οι παράμετροι μεταβάλλονται σε έναν κυλιόμενο χρονικό ορίζοντα και επιτυγχάνεται πρόβλεψη της ταχύτητας έως 10% για δέκα βήματα στο μέλλον. Διερευνάται η χρήση μοντέλων καθοδηγούμενων από τα δεδομένα σε συνθήκες μεικτής κυκλοφορίας χωρίς τήρηση των λωρίδων κυκλοφορίας και με μεγάλη ποικιλία ως προς τον τύπο των οχημάτων, κοινά χαρακτηριστικά των αναπτυσσόμενων χωρών. Αν και τα κλασσικά πρότυπα ακολουθίας οχημάτων είναι θεωρητικά τεκμηριωμένα, τα πρότυπα βασισμένα σε δεδομένα προσφέρουν μεγαλύτερη ευελιξία και επιτρέπουν την εύκολη ενσωμάτωση νέων μεταβλητών. Τα αποτελέσματα υποδεικνύουν ότι τα πρότυπα που βασίζονται σε δεδομένα μπορούν να συμβάλλουν στην εκτίμηση πιο αξιόπιστων μικροσκοπικών προτύπων.

A Simulation Study for Minimizing Operating Speed Variation of Multilane Highways by Controlling Access

Abstract: Traffic speed is generally considered a main issue in roadway safety. Previous studies show that faster travel is not necessarily associated with an increased risk of being involved in a crash. When vehicles travel at the same speed in the same direction (even high speeds, as on interstates), they are not passing one another and cannot collide as long as they maintain the same speed. Conversely, the frequency of crashes increases when vehicles are traveling at different rates of speed. There is no doubt that the greater speed variation is, the greater the number of interactions among vehicles is, resulting in higher crash potential. This research tries to recognize all primary factors that are associated with speed variation (dispersion) on multilane highways, including roadway access density, which is considered to be the most distinct contributing factor. Additionally, other factors are considered for this purpose, for example: configuration of speed limits, characteristics of traffic volume, geometrics of roadways, driver behavior, environmental factors, etc. A microscopic traffic simulation method based on TSIS (Traffic Software Integrated System) is utilized to exploit mathematical models to quantify the influences of all possible factors on speed variation.

The Application of 3D Visual Simulation Technology to Highway and Tunnel Emergency Training and Management

Abstract: The 1999 fire inside the Mont Blanc Tunnel led the French authorities to speed up the process - already planned - of improving the safety of tunnels and roads. The new regulations defined specific measures to ensure user safety and emergency services and led to new requirements regarding the training of operators. Indeed, in this highly regulated environment, operations staff are under increasing pressure. That is why they should receive appropriate training not only during their initial learning, but also later, to ensure the continuous improvement of skills and behavior particularly in crisis situations. To be effective, these programs need to immerse operators in situations similar to those they might encounter in real life: management of a serious incident, communication with stakeholders, and application of complex procedures. For this industry, BMIA has developed an innovative system known as G'Val, a unique solution of 3D real-time traffic simulation on the roads and in tunnels, directly controlled by an original Traffic Control Device, based on the UC-win/Road software from Forum8. This simulator is used to train control center operators, to validate new operating rules and features, or to evaluate new traffic software. The simulator allows personnel to be trained in a simulated environment that exactly reproduces the real environment: CCTV monitoring, HMI and ADI alarms, complete control over road equipment, driving of emergency vehicles and communication with stakeholders. Predefined scenarios can be played, and real situations (accidents, beaconing), or rarer incidents (fire and smoke in a tunnel) replayed. With this simulation operator knowledge of existing procedures can be checked and implementation of new procedures tested. The ability to network multiple simulators permits training of operators in complex situations and assessment of their reactions and behavior under stress.