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- 2026SIDRA Glossary of Road Traffic Analysis Terms
This glossary has been prepared to include the terminology of the SIDRA INTERSECTION and SIDRA TRIP software. This updated version includes traffic assignment terms with the inclusion of SIDRA ASSIGN functionality in SIDRA…
- 2025SIDRA Roundabout Presentation - TORUS Webinar Nov 2025
This is a short overview of the SIDRA INTERSECTION software for roundabout capacity and performance analysis for single intersections, corridors and networks, presented at the Joint Transoft Solutions - SIDRA SOLUTIONS Webinar,…
- 2025A Roundabout Capacity Survey Method Using Gap Acceptance Cycles and Vehicle Trajectory Data
This detailed research report describes a new gap acceptance capacity survey method using vehicle trajectory data and gap acceptance cycles based on a traffic signal analogy approach. Developed using data at a single-lane…
- 2025New Survey Method for Calibration of Roundabout Capacity Models
A new survey method has been developed under funding by SIDRA SOLUTIONS to estimate roundabout capacity by utilizing detailed vehicle trajectory data. This method uses gap acceptance cycles based on a signal analogy concept that…
- 2025A New Roundabout Capacity Survey Method
This presentation gives a summary of a new method for conducting roundabout capacity surveys using detailed vehicle trajectory data developed under funding by SIDRA SOLUTIONS. The method observes gap acceptance cycles based on…
- 2025SIDRA Model Extensions for the Highway Capacity Manual
This technical note and TRB HCQS Committee Meeting presentation give information about the SIDRA model extensions offered for the US Highway Capacity Manual (HCM), SIDRA research contributions to the HCM, and further information…
- 2024Traffic modeling: micro-analytical meets micro-simulation
Powerful concepts have been developed and used in traffic modelling for a long time. These apply to key elements of analytical models and are related to methods used in microsimulation models. This presentation recommends that…
- 2024SIDRA Multimodal Capacity and Performance Analysis for Roundabouts
This TRB Annual Meeting presentation is a contribution to a session on areas where multimodal capacity and performance models for roundabouts can be improved in future versions of the Highway Capacity Manual (HCM). The…
- 2023Use of SCATS MF to Calibrate SIDRA Saturation Flow
This document presents a discussion on the use of the Maximum Flow values recorded in the SCATS traffic control system (SCATS MF) for calibrating Saturation Flow in SIDRA models of signalised intersections. While the concept of…
- 2023What is good about analytical traffic modelling?
This document presents a brief discussion of why traffic modellers use analytical models for traffic and transport planning, management, design and operations purposes. The applications include traffic impact analysis, roundabout…
- 2023Network Analysis under Variable Demand Conditions - The SIDRA Method
The SIDRA method for Variable Demand Analysis for intersections and networks is a new feature introduced in SIDRA INTERSECTION Version 9.1. The Variable Demand Model is useful for multi-period analysis of persistent congestion.…
- 2022Intersection Level of Service and Performance Discrepancies
The intersection level of service (LOS) method, especially as specified in the US Highway Capacity Manual (HCM), has been around for a long time. It continues to be discussed with various related issues raised by professionals.…
- 2022A Comparative Analysis of Exponential and Linear Roundabout Capacity Models Using HCM Research Data
This technical note and conference presentation give the results of an investigation to assess basic exponential (non-linear) and linear model forms used in practice for roundabout capacity estimation. Best fit regression and…
- 2022Searching for a Gap Acceptance Theory Basis for Linear Capacity Models
This technical note presents an investigation to explore if a linear capacity model can be derived as a gap-acceptance capacity model assuming a uniform or linear arrival headway distribution of the opposing traffic stream. The…
- 2022HCM 6 Extended Roundabout Capacity Model in SIDRA INTERSECTION
This conference presentation describes an extended version of the HCM Edition 6 Roundabout Capacity Model. As roundabouts become more widely adopted, a greater variety of multi-lane configurations and more frequent use of…
- 2021How many are enough?: Investigating the effectiveness of multiple conflict indicators for crash frequency-by-severity estimation by automated traffic conflict analysis
Traffic conflict techniques are a viable alternative to crash-based safety assessments and are particularly well suited to evaluating emerging technologies such as connected and automated vehicles for which crash data are…
- 2021A bivariate extreme value model for estimating crash frequency by severity using traffic conflicts
Estimating crash frequency by severity levels using traffic conflicts remains relatively unexplored in conflict-based traffic safety assessment, limiting its application scope and appeal compared to traditional methods. No…
- 2021Calibration and Validation of a Volume-Delay Function Using a Genetic Algorithm
In microscopic traffic networks, searching and optimization algorithms are commonly used to calibrate behavioral and performance models of simulators, such as genetic algorithms (GAs). GA applications in macroscopic simulations…
- 2021Management of Traffic Modelling - A critique of Austroads Report AP-R621-20, 2nd Edition.
In response to the detailed critique report entitled Transport Modelling for Project Managers - Critique of AUSTROADS Report AP-R621-20, Austroads carried out a major revision of Report AP-R621-20 and replaced it with Research…
- 2020Transport modelling for project managers - a critique of Austroads Report AP-R621-20
This technical note presents a critical review of the Austroads Report AP-R621-20 (Building Transport Modelling Management Capability) for project managers, modelling guide developers and modellers using analytical and simulation…
- 2019Optimal Vehicle Trajectory Planning With Control Constraints and Recursive Implementation for Automated On-Ramp Merging
This paper proposes a vehicle trajectory planning method for automated on-ramp merging. Trajectory planning tasks of an on-ramp merging vehicle and a mainline facilitating vehicle are formulated as two related optimal control…
- 2019Comparing Roundabout and Metered Roundabout Performance under Different Traffic Conditions
This paper reports results of research comparing the performance of an intersection under two types of control, roundabouts and metered roundabouts. The experimental design evaluated a four-leg at-grade roundabout with several…
- 2019Costing Traffic Congestion
While many researchers have offered various definitions of traffic congestion, there is no universally accepted definition, and different variables have been introduced to measure traffic congestion. This paper aims to examine…
- 2019Are Models becoming smarter than Modellers?
Models in software applications are becoming increasingly more sophisticated. Artificial Intelligence becoming visible in all areas of our lives. Is this making modellers smarter or are they left behind? How is all this affecting…
- 2018Modelling the Net Traffic Congestion Impact of Bus Operations in Melbourne
Bus services can be seen as a way to reduce traffic congestion where they can encourage a mode shift from car. However, they can also generate negative effects on traffic flow due to stop-start operations at bus stops. This paper…
- 2018Gap Acceptance Cycles for Modelling Roundabout Capacity and Performance
Gap-acceptance theory has been used widely for estimation of capacity at unsignalised roundabouts and two-way sign-controlled intersections. This paper discusses the use of the gap-acceptance method beyond modelling capacity. The…
- 2018Comparing Common Control Group treatment and signal coordination of intersections with separate controllers
Common Control Group is a SIDRA INTERSECTION software term used for a group of signalised intersections controlled by a single signal controller. This is relevant to the modelling of signalised paired (closely-spaced)…
- 2017Does Combining Transit Signal Priority with Dedicated Bus Lanes or Queue Jump Lanes at Multiple Intersections Create Multiplier Effects?
An extensive body of literature deals with the design and operation of public transport (PT) priority measures. However, there is a need to understand whether providing transit signal priority with dedicated bus lanes (TSPwDBL)…
- 2017Traffic models in the era of big data
A useful definition of the term "Big Data" refers to the use of predictive analytics, user behaviour analytics, or certain other advanced data analytics methods that extract value from data, and seldom to a particular size of…
- 2017Roundabouts Lessons Learned
This presentation is a summary of some of the key lessons the author has learned in 14 years of planning and design of roundabouts in the USA. It provides a good general overview of many different aspects of design and operation…
- 2017Roundabout Model Comparison Table
This short document presents a table comparing main features of three roundabout capacity models, namely the Australian model as implemented in the SIDRA INTERSECTION software, the HCM Edition 6 model described in Chapter 22 of…
- 2017An Assessment of the Highway Capacity Manual Edition 6 Roundabout Capacity Model
The latest TRB Highway Capacity Manual (HCM) Edition 6 (2016) introduced major changes to the roundabout capacity model parameters compared with those given in the HCM 2010 Edition. This paper presents an assessment of the HCM…
- 2017A Comparison of Two Roundabout Capacity Models
This paper presents the results of a detailed comparison of two roundabout capacity models, namely a model developed by the first author of this paper based on her research conducted in Poland (referred to as the Macioszek model)…
- 2017Establishing Trust Between Fully-Connected Autonomous Vehicles
The development of autonomous vehicles by automotive and technology companies, is an exciting and active area of research receiving much media attention. Fascination extends from the independence of these vehicles, gained by…
- 2017Analytical and simulation approaches to understand combined effects of transit signal priority and road-space priority measures
Transit signal priority (TSP) may be combined with road-space priority (RSP) measures to increase its effectiveness. Previous studies have investigated the combination of TSP and RSP measures, such as TSP with dedicated bus lanes…
- 2016Impact of Information on Risk Attitudes: Implications on Valuation of Reliability and Information
Risk attitudes are an important behavioural characteristic that influences people's valuation of information and reliability. In a transport context, information has become widely accessible to road users through ITS systems, GPS…
- 2016Modelling Disrupted Transport Network Behaviour
Current transport modelling tools, utilised for maintenance and development of road infrastructure, assign traffic throughout a network based on traditional equilibrium concepts. These models assume rationality, perfect network…
- 2016Recent Innovations and Applications in SIDRA INTERSECTION: Lane-Based Network Model
The SIDRA INTERSECTION network model is largely built on the sound foundation of the lane-based methodology used in the single intersection model proven via research and used in practice during the last three decades. The network…
- 2016Comparing Lane Based and Lane-Group Based Models of Signalised Intersection Networks
Two analytical approaches for modelling signalised intersection networks for the assessment of signal coordination quality as a fundamental element of network performance analysis are compared. These are (i) the traditional model…
- 2016How reliable is the Bluetooth-based origin-destination data
The Origin-Destination data have always been considered as the core information in transport modelling and planning as they make it possible to understand the movement patterns in a particular area of interest, during a…
- 2015Strategic Traffic Assignment: Models and Applications to Capture Day-to-Day Flow Volatility
Traffic assignment models continue to play a critical role in the transportation planning process. Furthermore, day-to-day traffic flow volatility is a wellacknowledged phenomenon that planners and researchers alike view as…
- 2015Departure Side Platforms: a road congestion mitigation measure
This study investigates the impact of level crossings closures on traffic congestion at crossings adjacent to or in the close proximity of railway stations, proposing the theory that making alterations to the infrastructure of…
- 2015Signal Platoon Patterns by Approach Lane use and Movement Class
The modelling of signal platoon patterns is further enhanced by using the Movement Class facility of the SIDRA INTERSECTION software. This is implemented by assigning two types of movements negotiating the network to Special…
- 2015Roundabouts in Australia: the state of the art on models and applications
This presentation discusses various aspects of roundabouts in Australia and gives a detailed summary of the main features of roundabout capacity and performance models for intersection and networks used in the SIDRA INTERSECTION…
- 2015Modelling Signal Platoon Patterns by Approach Lane use and Movement Class
A lane-based signal platoon progression model has been developed for estimating performance measures as a function of signal offsets, geometric design and flow conditions. the model takes into account midblock lane changes that…
- 2015Improvement of the West road corridor for accessing to the New Hospital of Lucca (Italy)
This paper presents results of the study of a road corridor in the historical city of Lucca, Tuscany, Italy. The corridor is about 1.5 km with seven different intersections along the corridor, including signalised and two-way…
- 2015Development of Network Signal Timing Methodology in SIDRA INTERSECTION
This presentation discusses main features of the network signal timing methodology which has been under development for the SIDRA INTERSECTION software (current Version 6.1 and the forthcoming Version 7). Direct elements of the…
- 2015Alternative Intersection Analysis Using SIDRA INTERSECTION
Alternative intersection and interchange treatments used in the USA and other countries include Diverging (Double Crossover) Diamond Interchange, Displaced Left-Turn Intersection, Median U-Turn Intersection, Restricted Crossing…
- 2015The Implications of Volatility in Day-to-Day Travel Flow and Road Capacity on Traffic Network Design Projects
This work addresses the traffic network design problem when day-to-day uncertainties in travel demand and link capacity are taken into account. Specifically, this work proposes a network design formulation that uses a strategic…
- 2014A Feasibility Study into the use of String Transport Systems for Passenger Rail in New South Wales
String Transport Systems (STS) are an efficient rail technology currently under development in Russia by String Technologies Unitsky. This technology utilises high-tension steel cables within concrete filler, in place of…
- 2014Recalibration of a vehicle power model for fuel and emission estimation and its effect on assessment of alternative intersection treatments
Estimation of fuel consumption and pollutant emissions for evaluating road traffic conditions is useful for environmental assessment in traffic design, operations and planning. This also forms the basis of operating cost…
- 2014Modelling Queue Spillback and Nearby Signal Effects in a Roundabout Corridor
This paper discusses two aspects of modelling roundabout corridors: (i) a lane-based model of queue spillback, i.e. blockage of upstream lanes by queues formed in downstream lanes and the resulting capacity reduction in those…
- 2014Measuring and Assessing Traffic Congestion: A Case Study
Measuring and assessing traffic congestion can be a difficult task in practice. This paper presents a case study investigating a highly congested signalized intersection in Melbourne. This is the intersection of Alexandra Parade…
- 2014Analysis of Fuel Consumption and Emissions at Roundabout with Slip Lane, using SIDRA and Validation by MOVES Simulation
SIDRA tool enables researchers and practitioners to model vehicle emissions at a project level. Vehicular fuel consumption and emissions performance (CO2 and CO) are simulated within single-lane roundabouts, with a one approach…
- 2014A New Lane-Based Model for Platooned Patterns at Closely-Spaced Signalised Intersections
An analytical lane-based method for determining platoon patterns at closely-spaced signalised intersections is discussed. The method has been developed for the SIDRA INTERSECTION software. The traditional network models using…
- 2013Lane-Based Micro-Analytical Model of a Roundabout Corridor
This paper describes a lane-based micro-analytical network model and demonstrates it using a detailed example of staggered-T roundabouts. The model has been developed recently and implemented in the SIDRA INTERSECTION software…
- 2012Issues in Performance Assessment of Sign-Controlled Intersections
The capacity, performance and level of service assessment of intersections controlled by stop and give-way signs has special importance in the context of traffic impact assessment where the choice of sign-controlled intersections…
- 2012Calibrating Fuel Consumption and Emission Models for Modern Vehicles
Estimation of fuel consumption and pollutant emissions for evaluating traffic conditions is useful for environmental assessment in traffic design, operations and planning. This also forms the basis of operating cost modelling.…
- 2012An Improved Method for Estimating Sign-Controlled Intersection Capacity
This paper discusses the gap acceptance parameters recommended by the Austroads Road Design and Traffic Management Guides and the US Highway Capacity Manual, and describes a new method developed for the SIDRA INTERSECTION…
- 2011Some Common and Differing Aspects of Alternative Models for Roundabout Capacity and Performance Estimation
This paper considers three well-known analytical models of roundabout capacity, and discusses some common and differing aspects of these models. The models considered are the US Highway Capacity Manual 2010 (HCM 2010) model,…
- 2011Roundabout Metering Signals: Capacity, Performance and Timing
Roundabout metering signals help to create gaps in the circulating stream to solve the problem of excessive queuing and delays caused by unbalanced flow patterns and high demand flow levels. This paper gives a brief summary of…
- 2011Roundabout Design and Capacity Analysis in Australia and New Zealand
This presentation highlights various aspects of roundabouts in AUSTRALIA and NEW ZEALAND in response to the following objective of the International Roundabout Design and Capacity Seminar: Present an overview of typical…
- 2011ROUNDABOUTS - Comments on the SIDRA INTERSECTION Model and the TRL (UK) Linear Regression Model
There has been some controversy in relation to the lane-based gap-acceptance model used in SIDRA INTERSECTION software vs the approach-based linear regression (UK TRL "empirical") model used in RODEL and ARCADY software for…
- 2011Measuring Traffic Congestion
This paper examines traffic congestion, particularly in light of the growing public emphasis on the cost of congestion. Traffic behaviour and management are discussed in the context of congestion and its various causes. The…
- 2011Analysis of Single-Lane Roundabout Slip Lanes using SIDRA
Roundabout intersections, increasingly used in the U.S., sometimes incorporate slip lanes to facilitate right-turning traffic flow and reduce delay, thereby increasing capacity and safety. Performance of a single-lane roundabout…
- 2011An assessment of the Highway Capacity Manual 2010 roundabout capacity model
This paper presents an assessment of the roundabout capacity model given in the new Highway Capacity Manual 2010 (HCM 2010) with a focus in its use in the SIDRA INTERSECTION software. The model can be viewed as a non-linear…
- 2010Guidelines for Selecting Techniques for the Modelling of Road Network Operations
This paper describes guidelines for the selection of the appropriate modelling techniques for the analysis of road network operation schemes. The guidelines include a worksheet that facilitates in the assessment of four major…
- 2009Active Transport Journey Planner Methodology
This research endeavours to define and develop a methodology based on ‘multi-objective linear programming’ and ‘multi criteria analysis’, to rank all the admissible transport options from home to the university based on total…
- 2009Evaluating Roundabout Capacity, Level of Service and Performance
This paper discusses various findings and recommendations of the NCHRP Report 572 on roundabout capacity and level of service. Discussions include issues related to the finding of lower capacity of roundabouts in the USA compared…
- 2008Variable User Charging: Experiences and Extensions in a World of Carbon Emissions
Road pricing as an economic construct is not a new phenomenon in transportation research. Whilst fuel taxing and toll roads are common within Australia, these initiatives are primarily aimed at road infrastructure financing.…
- 2008The Relationship between Capacity and Driver Behaviour
Analytical models use traffic stream capacity as a basic parameter in traffic performance estimation. Traffic characteristics that affect capacity are not often clearly explained or understood. This causes difficulties in…
- 2008Speed Control at Roundabouts - use of Maximum Entry Path Radii
This paper proposes a method for speed control at roundabouts based on setting maximum values of entry path radii for roundabouts, in lieu of the deflection criteria used in the current Austroads (1993) roundabout guide. The…
- 2008Roundabouts in Australia
This paper presents a collation of comments received from Australian traffic and transport professionals in response to a survey about the current status of roundabouts in Australia. The survey posed questions related to the…
- 2008An Investigation of the Performance of Roundabouts with Metering Signals
A major project was undertaken for VicRoads, the state transport authority in Victoria, to investigate the performance of roundabouts with metering signals in Melbourne, Australia. Five multi-lane roundabout sites were chosen for…
- 2007Microsimulation and Analytical Models for Traffic Engineering
This presentation discusses relationships between microsimulation and analytical models. The following paper is recommended in relation to this presentation: Akçelik, R., and Besley M. (2001). Microsimulation and analytical…
- 2007A Review of Gap-Acceptance Capacity Models
Gap-acceptance capacity models apply to the analysis of minor movements at two-way stop and give-way (yield) sign-controlled intersections, entry streams at roundabouts and opposed (permitted) turns at signalised intersections.…
- 2006The Freight Capacity Model: A tool for exploring the future of road freight and its impact on the Environment
With the freight task predicted to double in the next 20 years, one reaction is to increase the fleet size to satisfy the increased demand over time. However from any perspective, let alone environmental, this is an unsustainable…
- 2006Speed - Flow and Bunching Models for Uninterrupted Flows
Akçelik's time-dependent speed - flow model based on queuing theory concepts is used to develop alternative versions of the HCM speed - flow models for basic freeway segments, multilane highways and urban streets. The…
- 2006Operating Cost, Fuel Consumption and Pollutant Emission Savings at a Roundabout with METERING SIGNALS
Estimation of operating cost, fuel consumption and pollutant emissions for evaluating intersection traffic conditions is useful for design, operations and planning purposes in traffic management. A four-mode elemental (drive…
- 2005Management of Competing Demands On Urban Freight Corridors
This paper compares the performance under various scenarios of an urban traffic corridor section subjected to a range of vehicle types. A micro-simulation-based model of the corridor was developed from first principles to…
- 2005Roundabouts with Metering Signals
A conceptual analysis model has been developed by Akcelik and Associates Pty Ltd (May 2001) to analysis roundabouts with metering signals. This mode was tested using a range of data to verify its operation and to test its…
- 2005Roundabout Model Calibration Issues and a Case Study
This paper discusses issues related to calibration of models for analysing roundabout capacity and performance. Two basic calibration methods that can be used for gap-acceptance and linear regression methods are described. A case…
- 2005Capacity and Performance Analysis of Roundabout Metering Signals
This paper describes a method for the analysis of capacity and performance of roundabouts operating with metering signals. When low capacity conditions occur during peak demand flow periods, for example due to unbalanced flow…
- 2004Examining Travel Time Variability Using AVI Data
Knowledge of travel time variability is valuable for improving the reliability of traffic information services and increasing the accuracy of travel time predictions. To identify the source of travel time variability, information…
- 2004Using The Six Principles Of Persuasion To Promote Travel Behavior Change - Preliminary Findings Of A Travelsmart Pilot Test
Policies aiming to increase the sustainability in urban transport often face the problem of overcoming unsustainable behavior patterns that are principally centered arround the car and largely dominated by routine based mode…
- 2004Stops & Goes of Traffic Signals
Transfund New Zealand funded the development of a signal audit methodology in order to examine the safety and efficiency of traffic signals. A representative number of signal installations across nine territorial local…
- 2004Roundabouts with Unbalanced Flow Patterns
An improved understanding of the effect of origin-destination demand pattern of traffic on roundabout capacity and level of service will help towards designing new roundabouts that will cope with future increases in demand levels…
- 2004Differences between the AUSTROADS Roundabout Guide and aaSIDRA Roundabout Analysis Methods
This paper presents a summary of the differences between the AUSTROADS (1993) Roundabout Guide and aaSIDRA (SIDRA INTERSECTION) methods for roundabout capacity and performance analysis, and discusses some important aspects of the…
- 2004Comparison of Delay Estimates at Under-Saturated and Over-Saturated Pre-Timed Signalized Intersections
This paper presents results of research comparing delays estimated by a number of fixed-time signal delay models for a range of conditions extending from undersaturated to highly saturated. The delay models compared are a…
- 2003Mobility Considerations in Restricting Choice Sets in Modal Choice Models
Modal choice models are used to estimate the choices individuals make given the mode alternatives available to them. To better estimate the modal choice of an individual, attempts have been made to eliminate mode alternatives…
- 2003Improving Utilisation of Existing Public Transport Infrastructure by Allowing Bus Access to Tram Rights-Of-Way
Allocation of limited road space to competing user groups such as motorists, freight operators and public transport represents a growing challenge for transport engineers. This paper investigates one aspect of this, allowing…
- 2003Speed - Flow and Bunching Relationships for Uninterrupted Flows
A time-dependent speed - flow model based on queuing theory concepts (referred to as Akçelik's function in the literature) was previously used to develop alternative versions of the HCM speed - flow models for basic freeway…
- 2003Operating Cost, Fuel Consumption, and Emission Models in aaSIDRA and aaMotion
Estimation of operating cost, fuel consumption and pollutant emissions for evaluating intersection and mid-block traffic conditions is useful for design, operations and planning purposes in traffic management. This paper…
- 2003A Roundabout Case Study Comparing Capacity Estimates from Alternative Analytical Models
A single-lane roundabout case study from the United States is presented to compare capacity estimates from various analytical models. Some contradictory results that can be obtained from these models are highlighted and reasons…
- 2002Evaluation of Toll Collection Performance Using Traffic Simulation
With the continuing steady increase of vehicles on Brisbane roads, Brisbane is expected to experience gridlock situations by 2011 unless significant changes are made to roadways or methods of transport. Intelligent transport…
- 2002The Validity of Driving Simulator to Measure On-Road Driving Performance of Older Drivers
Objective: to validate a laboratory-based driving simulator in measuring on-road driving performance. Method: 129 community dwelling older adult drivers were assessed with both the simulator and an on-road tests. The driving…
- 2002A GPS Study of Car Following Theory
Car following theory is a small but important element of traffic modelling, which has been researched in various forms for over 50 years. It's description of a theoretical interaction of 2 or more cars while driving is an…
- 2002Speed - Flow Models for Uninterrupted Traffic Facilities
The report explains the uninterrupted travel speed concept, and describes the HCM speed - flow models for basic freeway segments and multilane highways as well as for the running time component of the HCM travel speed model for…
- 2002Roundabout Studies in Kansas
In 1997, the City of Manhattan installed the first roundabout in the state of Kansas State University research team conducted a field study of the operation of the roundabout. Comparison to similar traffic flows at…
- 2002Queue Discharge Flow and Speed Models for Signalised Intersections
This paper describes the exponential queue discharge flow rate and speed models, and presents a summary of model calibration results based on data from 18 intersections in Melbourne and Sydney, Australia. Relationships among…
- 2002Estimating Negotiation Radius, Distance and Speed for Vehicles using Roundabouts
New models for estimating negotiation radius, distance and speed values of through and turning vehicles at roundabouts were introduced in aaSIDRA version 2. The intersection negotiation parameters are important in determining…
- 2002Establishing Roundabout Guidelines for a State DOT
The purpose of this paper is to explore the process used and the issues encountered by the Missouri Department of Transportation (MoDOT) in developing the first phase of its state-wide roundabout guide. A number of basic…
- 2001Progression Factors in the HCM 2000 Queue and Delay Models for Traffic Signals
This Technical Note specifies various conditions for use in implementing the HCM 2000 progression factors for delay and back of queue. The progression factor equations are given, the implementation conditions (constraints) are…
- 2001Pedestrian Movement Characteristics at Signalised Intersections
This paper presents findings of an investigation of pedestrian movement characteristics at intersection signalised crossings. The main objective of the study was to obtain information on pedestrian crossing speeds used for signal…
- 2001Microsimulation and Analytical Methods for Modelling Urban Traffic
Microsimulation models can help with the analysis of complex traffic problems in urban areas, alongside the analytical techniques that are in use. However, concerns are often expressed regarding misuse of microsimulation. This…
- 2001HCM 2000 Back of Queue Model for Signalised Intersections
A major improvement in the latest edition of the US Highway Capacity Manual is the introduction of a back of queue model for signalised intersections. The model was derived by simplification of the more general form used in the…
- 2001Evaluation of Roundabout Performance using SIDRA
This paper compares the performance of roundabouts with four leg intersections under yield control, two- and four-way stop control, and signal control for various traffic conditions using the SIDRA package. Such conditions…
- 2001An Investigation of Pedestrian Movement Characteristics at Mid-Block Signalised Crossings
This report presents findings of an investigation pedestrian movement characteristics at three pedestrian actuated mid-block signalised crossings in Melbourne, Australia. Two surveys were carried out at each site, one on a…
- 2001Acceleration and Deceleration Models
Modelling of acceleration and deceleration distances and times associated with speed change cycles under normal driving conditions is essential for the analysis of operating cost, fuel consumption and pollutant emissions, as well…
- 2000Incident Detection by Fractal Dimension Analysis of Loop Detector Data
This paper describes a research project which aimed to demonstrate the feasibility of using Fractal Dimension analysis of speed, occupancy and flow data for automatic incident detection (AID). Non-recurrent congestion resulting…
- 2000On the Validity of Some Traffic Engineering Folklore
This paper presents commentary on selected points from an earlier article titled "Traffic Engineering Folklore" which presented "a summary of quick and easy approximations to traffic related problems" based on an Australia-wide…
- 2000Field Assessment of the Performance of Computer-Based Signal Timing Models at Individual Intersections in North Carolina
North Carolina State University carried out a comprehensive study and evaluation of alternative software packages for signalised intersections (SIDRA, TRANSYT, HCS/HCM, Signal 94, HCM/Cinema, EVIPAS) for the North Carolina…
- 1999Traffic Management Performance - Development of the Traffic Frustration Index
This consolidated report covers the ARRB TR research project RC7111 “Traffic Management Performance Measures” funded by Austroads (Project N.RUM.9805). This investigation set out to discover whether a Traffic Frustration Index…
- 1999Fundamental Relationships for Traffic Flows at Signalised Intersections
This report presents findings of a study of fundamental traffic characteristics at signalised intersections based on surveys of queue discharge headways and speeds for individual vehicles and jam spacings at eighteen…
- 1999Fundamental Relationships for Freeway Traffic Flows
This report presents findings of a study of fundamental characteristics of freeway traffic flows based on analysis of individual vehicle data collected on the Eastern Freeway in Melbourne under both saturated and unsaturated…
- 1998
- 1998Modern Roundabout Practice in the United States
This synthesis presents information on current practices with respect to the planning, design, and operation of modern roundabouts in the United States. It will be of interest to state and local highway design engineers, traffic…
- 1998An evaluation of SCATS Master Isolated control
The well-known SCATS wide-area traffic control system has a unique feature for the control of a single non-coordinated signalised intersection known as SCATS Master Isolated control. The effectiveness of this control was…
- 1998A Comparison of Three Delay Models for Sign-Controlled Intersections and Roundabouts
The results of an evaluation of three analytical delay models for unsignalised intersections are presented. The delay models studied are the Highway Capacity Manual Chapter 10 (HCM 94) Model, the Ak_elik - Troutbeck model, and…
- 1997Three-Laning a Two-Lane Roundabout - The Outcomes
Using aaSIDRA (SIDRA INTERSECTION) software, VicRoads engineers redesigned a highly congested two-lane roundabout in Melbourne, Australia as a three-lane roundabout eliminating persistent congestion. Detailed field surveys were…
- 1997Recent Research on Actuated Signal Timing and Performance Evaluation and its Application in SIDRA 5
Results of extensive research on actuated signal control methods are presented. A method for predicting actuated signal timings, and analytical models for predicting various performance statistics (delay, queue length, queue…
- 1997Lane-By-Lane Modelling of Unequal Lane use and Flares at Roundabouts and Signalised Intersections: The SIDRA Solution
This paper was prepared in response to two articles, "ARCADY Health Warning: Account for unequal lane usage or risk damaging the Public Purse!" by B. Chard, and "Modelling flares at traffic signal-controlled junctions" B.F.…
- 1997Fundamental Traffic Variables in Adaptive Control and the SCATS DS Parameter
This paper discusses the fundamental traffic variables relevant to adaptive traffic control, monitoring and incident detection. The variables considered include headway, gap, occupancy and space times, vehicle spacing, gap length…
- 1997Analysis of Roundabout Performance by Modelling Approach Flow Interactions
An analytical method for estimating roundabout entry lane capacity and performance measures is presented. The method is based on modelling the gap acceptance process that takes place in real-life roundabout operation. Unlike past…
- 1996Relating Flow, Density, Speed and Travel Time Models for Uninterrupted and Interrupted Traffic
A vast amount of literature exists on the fundamental speed-density_ flow models of traffic theory and various travel time (cost)-flow models used for transport planning and demand management purposes. There is often a confusion…
- 1996Progression Factor for Queue Length and Other Queue-Related Statistics
A method presented that extends the U.S. Highway Capacity Manual (HCM) delay progression factor method to the prediction of queue length, queue clearance time, proportion queued (stopped), and queue move-up rate. These…
- 1996Performance of Roundabouts under Heavy Demand Conditions
The changes introduced in SIDRA for improved prediction of capacity and performance of roundabouts under heavy demand conditions are described. The new method, developed in response to problems observed at real-life roundabouts,…
- 1996Developing a set of Fuel Consumption and Emissions Models for use in Traffic Network Modelling
This paper introduces the results of a research project on the pollutant emissions and fuel consumption characteristics of mixed traffic streams under different levels of congestion. The project involved extensive testing of a…
- 1996ARCADY Health Warning: Account for Unequal Lane Usage or Risk Damaging the Public Purse!
The ARCADY computer program was first released in 1981. Developed by the Transport Research Laboratory, the program predicts capacities, queues and delays on roundabout approaches from user specified geometric and…
- 1995
- 1995
- 1995Not "the greatest new development in traffic engineering since the traffic signal"
This letter to the editor discusses a roundabout alternative to a signalised continuous flow intersection.
- 1994Traffic Performance Models for Unsignalised Intersections and Fixed-Time Signals
New analytical models are presented for predicting various performance statistics for traffic in approach lanes controlled by give-way and stop signs and fixed-time signals. The models are also applicable to roundabouts. An…
- 1994Route Choice and Signal Control: The Potential for Integrated Route Guidance
Review of the publication titled "Route Choice and Signal Control: The potential for Integrated Route Guidance" by Tom Van Vuren and Dirck Van Vliet. (Institute for Transport Studies Series, No.5)
- 1994Recalibrating SIDRA's Saturation Flow Estimation Models
This paper outlines the principal results of a major research project into saturation flows at signalised intersections in Melbourne. The results of this research were used to recalibrate the saturation flow models use by SIDRA.…
- 1994Overflow Queues and Delays with Random and Platooned Arrivals at Signalized Intersections
The traditional two-term analytical model for predicting delays, queues and stops with random arrivals as found at isolated signalized intersections is extended to the case of platooned arrivals. The work was carried out in the…
- 1994Overflow Delay Estimation for a Simple Intersection with Fully Actuated Signal Control
Queueing delay at a traffic signal can be generally estimated as the sum of two components, uniform delay and overflow delay. The delay formula in the 1985 Highway Capacity Manual (HCM) applies primarily to lane groups under…
- 1994Gap Acceptance Modelling by Traffic Signal Analogy
New capacity and performance (delay, queue length, proportion queued and queue move-up rate) models are presented for unsignalised intersections (roundabouts and give-way and stop-sign control). The new models were developed by…
- 1994Estimation of Green Times and Cycle Time for Vehicle-Actuated Signals
An analytical method for estimating average green times and cycle time of vehicle-actuated signals is presented. The examination is limited to the operation of a basic actuated controller that uses passage detectors and a fixed…
- 1994Calibration of the Bunched Exponential Distribution of Arrival Headways
The estimation of arrival headways is fundamental to the modelling of gap acceptance processes for estimating capacities of sign-controlled traffic streams, roundabout entry streams and filter turns at signalised intersections.…
- 1993Overflow Delay at a Signalized Intersection Approach Influenced by an Upstream Signal: An Analytical Investigation
Some initial formulations of general overflow delay formulas that can be applied to isolated intersection approaches as well as those contained in a signalized arterial network are discussed. The main issues addressed are the…
- 1993Estimation of Delays at Traffic Signals for Variable Demand Conditions
This paper discusses a delay model for variable demand conditions. The model is applicable to the entire range of expected operations, including highly oversaturated conditions with initial queues at the start of the analysis…
- 1992The Effect of Heavy Vehicles on Saturation Flow at Signalised Intersections
This paper presents an analysis of the magnitudes of through car equivalents of heavy vehicles and the factors that influence them. The effect of various vehicles types on the rate of saturation flow at signalised intersections…
- 1992Oversaturation Delay Estimates with Consideration of Peaking
A deterministic oversaturation queueing model that uses a generalization of the peak hour factor concept of the U.S. Highway Capacity Manual (HCM) as a simple variable demand model is described. The model is used to explore…
- 1992Comparison of Roundabout Capacity and Delay Estimates from Analytical and Simulation Models
The predictions of capacity and delay for a single lane entry stream at a single lane roundabout by two simulation models, ModelC and INSECT, and two analytical models, ARRB Special Report 45 (SR 45) and SIDRA, are compared.
- 1991Travel Time Functions for Transport Planning Purposes: Davidson's Function, its Time-Dependent form and an Alternative Travel Time Function
A travel time function proposed by Davidson for transport planning purposes has been subject to much discussion and efforts of calibration including some controversy over the meaning of its parameters. This paper presents a…
- 1991Implementations of the Australian Roundabout Analysis Method in SIDRA
Progress towards the development of a comprehensive Australian method for the analysis of capacity and performance of roundabouts is reported. The new Australian roundabout design guide to be produced during 1991 will include a…
- 1991Akçelik's_Travel_Function_(for 1991 paper)_v1.xls
This Excel application includes calculations and graphs for various travel time functions discussed in this paper - AKÇELIK, R. (1991). Travel Time Functions for Transport Planning Purposes: Davidson's Function, its…
- 1990SIDRA for the Highway Capacity Manual
This paper presents information about the HCM option in the SIDRA software and discusses various aspects of the 1985 HCM / HCS methodology as well as the proposals to modify it. An application of SIDRA to an example from the HCM…
- 1990Green Splits with Priority to Selected Movements
This article describes a green split computation method that allows for priority specification for selected movements. The method described in this paper allows for (1) unequal practical degrees of saturation; (2) minimum and…
- 1990Comments on the Application of Queueing Theory to Delays at Signals
This technical note presents comments on the results of the application of queueing theory to delays at signalised intersections given in a paper by Blunden and Vandebona. The relationship between the Australian and other delay…
- 1989On the Estimation of Lane Flows for Intersection Analysis
This article responds to the question "Which principle should be used as a basis for estimating lane flows at the approaches to an intersection, and how does this principle relate to the lane choice decisions of individual…
- 1989Efficiency and Drag in the Power-Based Model of Fuel Consumption
The efficiency and drag parameters in the instantaneous fuel consumption model are explained by comparing the model with the original power-based model developed at Sydney University, and relating the two models to a conceptual…
- 1988The Highway Capacity Manual delay formula for Signalised Intersections
The purpose of this article is to compare the 1985 U.S. Highway Capacity Manual (HCM) delay formula for signalized intersections with the Australian and Canadian formulas and to present a generalized form that embraces them all.…
- 1988Opposed Turns at Signalised Intersections: The Australian Method
An important element of capacity estimation at signalised intersections is the estimation of opposed (permissive) turn saturation flows. Although the basic modelling philosophies of the Highway Capacity Manual and Australian…
- 1988Capacity of a Shared Lane
The traditional adjustment factor and the new lane interaction methods for estimating the capacity of a shared lane at a signalised intersection are discussed. The adjustment factor method is needed when the shared lane is…
- 1987Estimating Effect of Vehicle Characteristics on Fuel Consumption
This technical note relates to a paper by Lam (4), “Estimating Fuel Consumption from Engine Size”, which recently appeared in this journal. Using the average travel speed model and data primarily from official fuel consumption…
- 1987Acceleration Profile Models for Vehicles in Road Traffic
Three new models of acceleration profile (a two-term sinusoidal, a three-term sinusoidal and a polynomial model) are described. A comparative evaluation of these three models and the previously known constant and…
- 1986Models for Estimation of Car Fuel Consumption in Urban Traffic
This article describes four fuel-consumption models. The models are interrelated and form part of the same modelling framework. A simpler model is derived from a more complicated model keeping the vehicle characteristic such as…
- 1986Fuel Consumption Analyses for Urban Traffic Management
A primary output from the fuel consumption research conducted by the Australian Road Research Board (ARRB) is the ARRB Special Report, Guide to Fuel Consumption Analyses. This article briefly summarizes the background of the…
- 1986Estimation of Car Fuel Consumption in Urban Traffic
The concept of a hierarchy of fuel consumption models is discussed where models of different levels of detail are applicable to the various scales of traffic systems. Fuel consumption models of four levels of detail are described…
- 1986An Energy-Related Model of Instantaneous Fuel Consumption
A model for estimating fuel consumption from instantaneous speed, acceleration and grade information is described. The model is suitable for use in the design of detailed traffic management schemes and, in particular, for…
- 1985Guide to Fuel Consumption Analysis for Urban Traffic Management
A substantial set of analysis techniques exist for the consideration of fuel consumption in urban traffic management. This report provides a guide to assist the traffic manager in selecting techniques which are appropriate to the…
- 1985An Interpretation of the Parameters in the Simple Average Travel Speed Model of Fuel Consumption
The simple average travel speed model of fuel consumption is widely used but the interpretation of its parameters and its areas of use have not been well understood. By deriving aggregate (but detailed) fuel consumption functions…
- 1985
- 1984SIDRA-2 does it Lane by Lane
SIDRA-2 implements the techniques described in the ARRB Research Report ARR No. 123 (Traffic Signals: Capacity and Timing Analysis). Although the fundamental principles and methods are the same, there are some important…
- 1983Progress in Fuel Consumption Modelling for Urban Traffic Management
Research Report ARR No. 124 collects together four papers presented at an ARRB Seminar on Fuel Consumption Modelling in 1981, as well as two subsequent papers. The objective of the Seminar was to focus on the issue of fuel…
- 1983Appraisal of Eight Small Area Traffic Management Tools
In this paper, eight small area traffic management packages or models are selected for appraisal. These models are useful for predicting the impact of traffic control measures before implementation. These measures include street…
- 1983A Hierarchy of Vehicle Fuel Consumption Models
A brief review of existing fuel consumption models is presented in the light of recent developments in this area. Various levels of models are identified with regards to model simplicity and accuracy. Relationships of the models…
- 1981Traffic Signals: Capacity and Timing Analysis
This report presents techniques for the analysis of capacity and timing requirements of traffic at signalised intersections. Its purpose is to both provide methods that can be used by the traffic engineer for detailed geometric…
- 1981Fuel Efficiency and other objectives in Traffic System Management
This paper discusses the objective of reducing vehicle fuel consumption in urban conditions in relation to other traffic management objectives. The discussion is based on the tactical issues related to these objectives aimed at…
- 1980Time-Dependent Expressions for Delay, Stop Rate and Queue Length at Traffic Signals
New expressions are presented for delay, stop rate and queue length at traffic signals operating in a fixed-time mode for flow conditions which last for a finite period of time. The emphasis is on the use of the overflow queue…
- 1980Stops at Traffic Signals
The queue length, delay and stop rate at isolated undersaturated signals are discussed. A formula is given for predicting stop rates. The formula allows for multiple stops in oversaturated cycles as well as a reduction due to…
- 1979A Graphical Explanation of the two Principles and two Techniques of Traffic Assignment
The purpose of the paper is to identify issues related to the two fundamental principles of traffic assignment and two techniques used for its solution. Firstly, the inter-relationships among the average, marginal total and…
- 1978X and Y in Traffic Signal Design
The paper proposes various improvements to the traffic signal design method with particular reference to the method used in Australia. The intersection degree of saturation, X is recommended for use as a simple measure of…
- 1976Route Control-Simulation Experiments
The paper investigates the potential savings in delay likely to result from the use of route control techniques in an urban network of streets where the dominant control mechanism is traffic signal control. The distinction is…
- 1976Route Control of Traffic in Urban Road Networks: Review and Principles
An important type of control which can be used for the control of traffic in urban areas in termed route control. In this paper, route control is defined and a comprehensive review of the related literature is presented. There is…
- 1975The re-distributional Effects of an area Traffic Control Policy
The purpose of this paper is fourfold: to point out that the assessment of the benefits of an ATC scheme cannot be made properly without consideration of the re-distributional effects; to emphasise the importance of the…
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