VISSIM Microscopic Simulation Research Articles

Exploring New Bus Priority Methods at Isolated Vehicle Actuated Junctions

Bus priority at traffic signals is necessary to improve bus travel time and service regularity especially when buses are late. It can be given by altering signal timings in favour of approaching buses. In usual practice this is achieved by either extending the green period or recalling the green stage early. In this study the usual extension and recall methods at VA signal controller have been developed and evaluated by using VISSIM microscopic simulation tool. Reasons for using VISSIM are also justified. During evaluation bus travel time savings and impact on general traffic has been considered. Performance of these methods on various junction types has been evaluated. New advanced bus priority methods have been developed and their performances have been compared with the existing methods.

Simple analytical models for estimating the queue lengths from probe vehicles at traffic signals

As mobile traffic sensor technology gets more attention, mathematical models are being developed that utilize this new data type in various intelligent transportation systems applications. This study introduces simple analytical estimation models for queue lengths from tracked or probe vehicles at traffic signals using stochastic modeling approach. Developed models estimate cycle-to-cycle queue lengths by using primary parameters such as arrival rate, probe vehicle proportions, and signal phase durations. Valuable probability distributions and moment generating functions for probe information types are formulated. Fully analytical closed-form expressions are given for the case ignoring the overflow queue and approximation models are presented for the overflow case. Derived models are compared with the results from VISSIM-microscopic simulation. Analytical steady-state and cycle-to-cycle estimation errors are also derived. Numerical examples are shown for the errors of these estimators that change with probe vehicle market penetration levels, arrival rates, and volume-to-capacity ratios.

Comparison of Emergency Vehicle Preemption methods using a Hardware-In-The-Loop simulation

Modern traffic signal control systems provide Emergency Vehicle Preemption (EVP), which provides the right-of-way to emergency vehicles in preference to other vehicles. Traffic engineers should select the best coordination recovery strategy at the end of the preemption in order to minimize any resulting disruptions. This paper compares the various EVP methods available with a controller used in the USA. The comparison was conducted in an urban corridor including four coordinated-actuated signals using a Hardware-In-the-Loop Simulation (HILS), which consisted of a well-calibrated VISSIM microscopic simulation model and four Type 170 controllers. The examined preemption strategies included shortway and dwell with different numbers of cycles for transition completion. The results of the comparison indicated that the resulting impact on the network-wide and intersection-specific performances varied with the selected EVP method. The results also indicated that the EVP function using a shortway transition method with two or three cycles worked the best, as it could minimize the impacts of EVP.

Design and Simulation of Urban Road Intersection Signal Linear Control System

In order to solve the contradiction between the supply and demand of traffic system, reduce traffic delay and improve the motor vehicle traffic capacity, the traffic engineering related theory knowledge is used and the existing research results at home and abroad is combined with. The purpose is to design the program: linear control system, based on the systemic analysis of some aspects such as the motor vehicle traffic capacity, traffic delay, signal period and peak hour traffic demand, which takes traffic delay time and capacity as evaluation index, by VISSIM microscopic simulation software, to compare and analyze the condition of traffic signal timing before and after optimization, which verifies that the linear control system effectively improve traffic capacity of the crossing and reduce the delay in the intersection.

Development of road traffic control by using integrated VISSIM-MATLAB simulation environment

The paper focuses on the simulation of signal control problems based on VISSIM microscopic simulator. VISSIM is a commonly used software in practice for diverse problems related to road traffic control. Beyond the standard use of VISSIM, advanced options are available. VISSIM COM interface and VISSIM DLL API may be used as well providing freedom to the traffic engineer. By exploiting the programming possibilities efficient simulations may be achieved. As additional possibility MATLAB may be involved in the traffic simulation as well creating an integrated environment with VISSIM. Thus, complex mathematical problems can be calculated online by MATLAB and used for VISSIM simulation.

Multicriteria ramp metering control considering environmental and traffic aspects

In this paper a multicriteria ramp metering control is designed considering three criteria: traffic performance and the local– and global effects of traffic emission. For real-time emission modeling a macroscopic modeling framework is proposed using an average-speed emission model. Based on the proposed model function cost functions regarding the global and local effects of traffic emission are stated. Traffic control is realized via ramp metering and the control input is optimized by using the NMPC technique. The closed-loop simulation of the designed control is carried out in VISSIM microscopic simulator.

Multi-objective signal control of urban junctions – Framework and a London case study

This paper presents an approach to multi-objective signal control using fuzzy logic. The signal control uses fuzzy logic where the membership functions are optimised according to the Bellman–Zadeh principle of fuzzy decision-making. This approach is both practical for the decision-maker and efficient, as it leads directly to a Pareto-optimal solution. Signal control priorities are ultimately a political decision. Therefore the tool developed in this research allows the traffic engineer to balance the objectives easily by setting acceptability and unacceptability thresholds for each objective. Particular attention is given in the example to pedestrian delays. The membership functions of the fuzzy logic are optimised by a genetic algorithm coupled to the VISSIM microscopic traffic simulator. The concept is illustrated with a case study of the Marylebone Road–Baker Street intersection in London at which pedestrians as well as vehicle flows are high. The results prove the feasibility of the framework and show the vehicle delays for a more pedestrian friendly signal control strategy.

Evaluation of Adaptive Maximum Feature in Actuated Traffic Controller

Several actuated traffic controllers contain the adaptive maximum feature, with which controllers can adjust the maximum green intervals for actuated phases within specified upper and lower limits according to fluctuating traffic demand. It has been difficult, however, to evaluate the merits of this and other features available in modern traffic controllers. Recent developments in traffic signal control system hardware and software technologies have now made it possible to evaluate controller features in a realistic and risk-free environment with hardware-in-the-loop simulation (HILS). HILS is a method of simulation in which one or more actual traffic signal controllers are physically linked with a microscopic traffic simulator. The performance of the adaptive maximum feature is demonstrated with HILS, which consists of an EPAC300 traffic controller and the VisSim microscopic simulation model. The demonstration was conducted at an isolated, fully actuated intersection in Richmond, Virginia. In a feasibility test, the HILS results indicated that the adaptive maximum feature was able to provide traffic signal control operations as efficiently as normal maximum green intervals optimized by Synchro. However, in a robustness test, where 15% changes in traffic volumes were considered, the adaptive maximum feature outperformed the normal settings for maximum green intervals.

Part 2: Traffic Signal Systems: Integration of Diamond Interchange and Ramp Metering Operations

The aim of this research was to develop operational strategies for integrating the operations between diamond interchange traffic signals and ramp metering signals. Integrated operational strategies were developed on the basis of the two commonly used diamond interchange phasing schemes: the basic three-phase scheme and the Texas Transportation Institute four-phase scheme. The key elements of the integration system and its operations include a proposed enhanced detection system and an operational algorithm. Through implementation of special signal timings at the diamond interchange, the traffic flows feeding the ramp meters can be effectively controlled and thus minimize ramp queues and the resulting need to flush the queues, which would possibly lead to freeway breakdown. The operational strategies were evaluated with VISSIM microscopic simulation under three general traffic demand scenarios—low, medium, and high—as characterized by the volume-to-capacity ratios at the metered ramps. The results of the e...

Integration of Diamond Interchange and Ramp Metering Operations

The aim of this research was to develop operational strategies for integrating the operations between diamond interchange traffic signals and ramp metering signals. Integrated operational strategies were developed on the basis of the two commonly used diamond interchange phasing schemes: the basic three-phase scheme and the Texas Transportation Institute four-phase scheme. The key elements of the integration system and its operations include a proposed enhanced detection system and an operational algorithm. Through implementation of special signal timings at the diamond interchange, the traffic flows feeding the ramp meters can be effectively controlled and thus minimize ramp queues and the resulting need to flush the queues, which would possibly lead to freeway breakdown. The operational strategies were evaluated with VISSIM microscopic simulation under three general traffic demand scenarios–-low, medium, and high–-as characterized by the volume-to-capacity ratios at the metered ramps. The results of the evaluation indicated that the integrated operations were most effective under a medium traffic demand scenario in preventing or delaying the onset of ramp metering queue flush, thereby reducing freeway breakdown and system delays.