Variability of traffic-flow measures across freeway lanes

1999 ◽  
Vol 26 (3) ◽  
pp. 270-281 ◽  
Author(s):  
Mark Carter ◽  
Hesham Rakha ◽  
Michel Van Aerde

On most freeways, a number of factors interact to produce lane-to-lane variations in speed and volume which are both site and volume dependent. The following paper explores and statistically verifies these variations using detector data and a combination of complementary techniques based on data collected for 30 days at 27 detector stations in May 1994 along the Queen Elizabeth Way freeway near Toronto, Ontario. The analysis indicates that considerable volume dependencies exist at each site, and that these dependencies are site specific. In addition to their independent variations, speed and flow are also shown to interact differently across different lanes and result in different underlying speed-flow relationships. The findings are intended to be relevant to the calibration of microscopic traffic simulation models and automatic incident detection algorithms. As such, the paper does not attempt to specifically identify the underlying causes for the variations, but rather attempts to recognize the aggregated effects of these causes in a fashion that would be useful to real-time freeway traffic management system control strategies relying solely on loop detector inputs.Key words: traffic-flow theory, traffic modeling, traffic simulation, incident-detection algorithms.

1994 ◽  
Vol 21 (3) ◽  
pp. 439-454 ◽  
Author(s):  
Bruce Hellinga ◽  
Michel Van Aerde

This paper discusses the application of the network traffic simulation model INTEGRATION to a 35-km section of Highway 401 in Toronto, Canada. Results for the eastbound direction from 4 a.m. to 12 noon are presented. Existing freeway conditions are quantified using data from the COMPASS freeway traffic management system and from a floating car travel time survey. Variations that exist in observed link flows and trip travel durations over time of day and day of week are examined. The extent to which COMPASS data meets the data requirements of the INTEGRATION model is examined. Since the current COMPASS system encompassed less than 50% of the network analyzed, complications arise in accurately estimating the prevailing time-varying origin–destination demands, as well as in comprehensively validating the simulation model's results. The present level of model calibration results in a correlation coefficient of estimated and observed link flows of 97.23%. This level of discrepancy is generally within the natural day-to-day variations that are inherent within the system. However, travel times estimated by the simulation model tend to be underestimated, particularly for the express lanes. Further model calibration, to improve the model's results, is deferred until more of the network is covered by COMPASS. Key words: traffic simulation, COMPASS, model calibration, model validation, speed–flow relationship.


1998 ◽  
Vol 1644 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Yunlong Zhang ◽  
Larry E. Owen ◽  
James E. Clark

The purpose of this paper is to explore various traffic modeling aspects and theories that may overcome some of the limitations in existing microscopic simulation models. A multiregime microscopic traffic simulation approach has been formulated featuring realistic and comprehensive carfollowing and lane-changing logic. A prototype implementation of the multiregime approach was developed in C++ and extensively tested. The multiregime simulation results demonstrate the efficiency and validity of the proposed models for a broad range of traffic scenarios. The test and validation results indicate that the model and program outperformed traditional methods and other existing traffic simulation programs. The validity and efficiency of the model is attributed to the fact that the regimes were added to the model incrementally to reflect increasing agreement with real-world traffic flow. The techniques and corresponding models will be used to improve existing microscopic traffic simulation models and programs.


2020 ◽  
Vol 1 (2) ◽  
pp. 65-70
Author(s):  
Daniel Shunu

In this study, a proposed intelligent traffic management system is presented making use of the wireless sensor network for improving traffic flow.  By making use of the clustering algorithm, VANET environment is utilized for the proposed system. The components of the proposed system include sensor node hardware, vehicle detection system through magnetometer, and UDP protocol for communication between the nodes. The intersection control agent receives the information about the vehicles and by making use of its algorithm, it dynamically changes the traffic light timings. By making use of the greedy algorithm, the system can be enhanced to a wider area by connecting multiple intersections.


2021 ◽  
Vol 13 (16) ◽  
pp. 8924
Author(s):  
Silvia Zaoli ◽  
Giovanni Scaini ◽  
Lorenzo Castelli

An environmentally and economically sustainable air traffic management system must rely on fast models to assess and compare various alternatives and decisions at the different flight planning levels. Due to the numerous interactions between flights, mathematical models to manage the traffic can be computationally time-consuming when considering a large number of flights to be optimised at the same time. Focusing on demand–capacity imbalances, this paper proposes an approach that permits to quickly obtain an approximate but acceptable solution of this problem. The approach consists in partitioning flights into subgroups that influence each other only weakly, solving the problem independently in each subgroup, and then aggregating the solutions. The core of the approach is a method to build a network representing the interactions among flights, and several options for the definition of an interaction are tested. The network is then partitioned with existing community detection algorithms. The results show that applying a strategic flight planning optimisation algorithm on each subgroup independently reduces significantly the computational time with respect to its application on the entire European air traffic network, at the cost of few and small violations of sector capacity constraints, much smaller than those actually observed on the day of operations.


Author(s):  
Shawn R. Wolfe ◽  
Peter A. Jarvis ◽  
Francis Y. Enomoto ◽  
Maarten Sierhuis ◽  
Bart-Jan van Putten

Today’s air traffic management system is not expected to scale to the projected increase in traffic over the next two decades. Enhancing collaboration between the controllers and the users of the airspace could lessen the impact of the resulting air traffic flow problems. The authors summarize a new concept that has been proposed for collaborative air traffic flow management, the problems it is meant to address, and our approach to evaluating the concept. The authors present their initial simulation design and experimental results, using several simple route selection strategies and traffic flow management approaches. Though their model is still in an early stage of development, these results have revealed interesting properties of the proposed concept that will guide their continued development, refinement of the model, and possibly influence other studies of traffic management elsewhere. Finally, they conclude with the challenges of validating the proposed concept through simulation and future work.


In General, two problems need to be solved in the traffic management system: road safety and capacity. In this paper, it is proposed to use a calculated way to optimize the cycle of a traffic light object in order to ensure the maximum capacity of the node of the road network. The calculation method is based to determining the optimal ratio of the number of lanes intended for vehicle traffic and the duration of a cycle of the traffic light object. Keywords capacity, street and road network, traffic flow, stop line, width of the roadway


1991 ◽  
Vol 18 (2) ◽  
pp. 191-200 ◽  
Author(s):  
John Morrall

The two basic problems facing the Trans-Canada Highway through Rogers Pass, namely the winter problem of adequate vehicle storage areas during avalanche control and the summer problem of maintaining an acceptable level of service by ensuring adequate passing opportunities, may be linked through a common denominator — passing lanes. This paper presents the findings of a recently completed study of the Trans-Canada Highway through Mount Revelstoke and Glacier National Park. The study method is based on the fact that traffic flow characteristics, highway conditions, and operational requirements vary considerably from season to season. Thus, the analysis was broken into two parts, namely a separate analysis of winter and summer conditions. A traffic simulation model was used to determine those locations that could serve as potential sites for passing lanes during summer. The traffic simulation model developed for the passing lane analysis utilized files that describe road geometry, summer traffic flow and composition, and vehicle performance. A separate simulation model was developed to determine vehicle storage requirements of ponding areas during avalanche control. The model developed for winter traffic characteristics also provided the basis for a flexible traffic management strategy. Cross-section elements were developed to accommodate an auxiliary lane to be used as a passing lane in summer and as a parking lane to increase the capacity of ponding areas during avalanche control in winter. Design requirements called for triple stacking of vehicles in ponding areas during avalanche control. To accommodate design year traffic volumes at an acceptable level of service during the summer months, 12 passing lanes totalling 23 km in length were recommended. Six ponding areas, totalling 4 km in length, are coincident with four of the passing lane locations. The paper concludes with a general discussion on the benefits of linking traffic simulation with geometric design to demonstrate how the design life of rural two-lane highways can be extended by the use of low-cost operational improvements such as passing lanes. Key words: highway planning and engineering, two-lane highways traffic management during avalanche stabilization, passing lanes, cross-section elements, Trans-Canada Highway.


1974 ◽  
Vol 1 (2) ◽  
pp. 141-149 ◽  
Author(s):  
Allen R. Cook

The advent of computer-controlled electronic freeway surveillance and control systems in the past decade represents a potentially significant new operational tool for traffic engineers in large urban areas. These systems are capable of responding to rapidly changing traffic conditions and in various demonstration projects they have proven useful in maintaining an acceptable level of service for freeway operations, reducing the extent and duration of traffic congestion, minimizing the adverse effects of accidents and other incidents on traffic operations, and reducing accident experience. Surveillance system goals and techniques for achieving these goals are reviewed in this paper with particular emphasis on the problem of managing unexpected capacity-reducing incident situations. Recent research has demonstrated the feasibility of detecting incidents from traffic flow data, which is desirable for surveillance purposes because this information can be used to implement control strategies which attempt in real-time to divert some freeway traffic to alternate routes. Some of the operational problems involved with freeway traffic management are discussed, particularly the generation of false alarms by detection algorithms and driver willingness to be diverted to alternate routes.


Sign in / Sign up

Export Citation Format

Share Document