New SI-8 Tutorials

We have released a new Network Data Input Dialog tutorial for SIDRA INTERSECTION 8. View this and others in the series via the links below.

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New SI-8 Videos

Movement Definitions Dialog
Right-Hand Traffic | Left-Hand Traffic

Route Data Dialog
Right-Hand Traffic | Left-Hand Traffic

Network Data Dialog
Right-Hand Traffic | Left-Hand Traffic

Other SI-8 Videos

Intersection Input Dialog
Right-Hand Traffic | Left-Hand Traffic

Route Configuration Dialog
Right-Hand Traffic Left-Hand Traffic

Network Configuration Dialog
Right-Hand Traffic | Left-Hand Traffic

Common Control Group (CCG) Input Dialogs
Right-Hand Traffic | Left-Hand Traffic

Network Timing Input Dialog
Right-Hand Traffic | Left-Hand Traffic

Site Phasing & Timing Input Dialog
Right-Hand Traffic | Left-Hand Traffic

Roundabouts Input Dialog
Right-Hand Traffic | Left-Hand Traffic

User Interface Videos
User Interface: Overview                           
User Interface: SITE Tab
User Interface: NETWORK tab
User Interface: ROUTE tab      

Excel Application for SIDRA INTERSECTION


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Click on the above playlist or links to watch video tutorials for SIDRA INTERSECTION. We will continue to issue new video tutorials for Version 8. Visit and subscribe to our YouTube channel for these and more tutorial videos.


Network Analysis Enhancements &
Improved Workflow

SIDRA INTERSECTION 8 offers much improved network model processing efficiency and much improved workflow efficiency through substantial enhancements to the user interface including improved visualisation and new output reports and displays. It also incorporates various important model improvements.

The following is a summary of the new features of SIDRA INTERSECTION 8.

More Powerful and Efficient Processing

Substantial increases are achieved in computing speeds for the iterative network analysis method enabling introduction of facilities for optimum timings as well as demand and sensitivity analysis for networks. Average computing speeds about 5 to 10 times faster than previous versions can be expected in Network analysis.

Increased efficiency of database operations have also been achieved and memory management enhancements have been introduced.

Enhanced User Interface

Significant user interface improvements introduced for ease of use of the software include:

  • graphical displays of Layout, Volumes, Phase Sequence and Movement IDs within most Site input dialogs for assisting the input data entry process and allowing direct in-display data entry;
  • various commands that were hidden in right-click menus in previous versions made available in the Site / Network / Route ribbon or in Site Output sections;
  • right-clicking an output report or display to open the relevant Site / Network / Route input menu and some display commands;
  • double-clicking Site / Network / Route name to open the relevant layout picture;
  • modified processing icon animation according to the new structure for Network model iterations;
  • where Network parameters override Site data, no need to process the Network again if any of the corresponding parameters are changed in Sites that constitute the Network;
  • improved Import Volume Data function;
  • simplified Volume Data Settings for Pedestrians;
  • various improvements in the CCG Phasing & Timing and the Network Data dialogs;
  • cancelling processing of multiple Sites and Networks;
  • option to include or exclude suffixes (Copy, Conversion, Import, Reversed) when Clone, Import, Convert, Reverse functions are used for Sites, Networks, Routes and Sequences;
  • improved Zoom Slider including a dialog to set exact zoom values.

Better Output Reports and Displays

These  have been enhanced significantly. New Site, Network and Route output reports and displays include:

  • Project Summary report using the new Site Category and Network Category parameters;
  • User Report facility based on user-defined report templates;
  • enhanced Input Comparison and Output Comparison facilities using results from different Projects;
  • Lane Changes, Lane Flows, Network Flows and Midblock Flows displays for the whole Network with pop-up boxes showing demand and arrival flows by movement class;
  • Approach Distances display for Networks;
  • Numerical values shown in all Network and Route Displays;
  • Signal Coordination displays in the form of Lane Displays for Sites, Networks and Routes, and Movement Displays for Sites;
  • Route Travel Performance report;
  • Saturation Flows report for signalised Sites;
  • Critical Movements display for signalised Sites with a phase - movement timings bar display and an ARR 123 style critical movement diagram;
  • Movement Timing display for Common Control Groups (CCGs) showing all movements of the CCG together;
  • Gap Acceptance Cycle Parameters included in the Sign Control Analysis and Roundabout Analysis reports.

Significant Network Model Improvements

Important model improvements have been made including:

  • Optimum Cycle Time for Networks;
  • Optimum Cycle Time and Optimum Maximum Green Settings for Common Control Groups;
  • new Phase Time calculation options;
  • improved treatment of Uncoordinated and Unconnected Sites for signal timing calculations;
  • Network Demand and Sensitivity analysis methods for design life, flow scale and parameter sensitivity;
  • Queue at Start of Green and Average Number of Cycles to Depart for signalised Sites;
  • enhanced methods used for stopping conditions in Network and Site model iterations with Network Model Variability Index and Site Model Variability Index parameters given in various output reports and displays;
  • improvements to the iterative method used for Site capacity and timing analyses resulting in fewer cases of unsettled results.

Free Upgrades at the time of a new Version release

Customers with valid COVER at time of release will be given a free upgrade from Version 7 to Version 8. If you have been issued a SIDRA INTERSECTION free upgrade, a new Licence ID number for the new product will be included and is viewable under Order history in your STORE ACCOUNT. This new Licence ID number is required to activate your new free upgrade licence.

Buy Online

SIDRA INTERSECTION 8 is now available for purchase from our online store.

Available in two versions - PLUS & NETWORK - these offer exactly the same functionality, except you can model up to 20 intersections with the NETWORK version. With the PLUS version you can model one or two intersections. 


Learn more about SIDRA INTERSECTION:




VOLUMES is an Excel application for SIDRA INTERSECTION 8 which allows specification of Volumes and related data within the Excel file, and processes a selected Site in a SIDRA INTERSECTION Project using data given in the Project file or in the Excel file, providing Volume Output, Intersection Output, Movement Output, Lane Output and Pedestrian Output data in Excel sheets. This has been developed in conjunction with SIDRA INTERSECTION API to provide additional capabilities for SIDRA INTERSECTION users. 

Visit the VOLUMES page on our support site to download .zip files containing the VOLUMES Excel Utility for SIDRA INTERSECTION 8 and various Sample Project files for use with this application.

Please refer to the SIDRA INTERSECTION User Guide for information on the use of this utility. A video tutorial will be available soon on our YouTube channel.

We are hiring!

The following jobs are listed on the Careers section of our website:

Customer Support & Administration
SIDRA Traffic Modeller


SIDRA INTERSECTION Workshops and USER GROUP MEETINGS are open for registration via Eventbrite. Be quick, some early bird ticket discounts are available for a limited time and limited allocation.

Visit our Directory to see a full listing of upcoming Workshops and User Group Meetings.


SIDRA INTERSECTION software is an aid for the design and evaluation of individual intersections and networks of intersections. It can be used to analyse signalised intersections (fixed-time / pretimed and actuated), signalised and unsignalised pedestrian crossings, roundabouts (unsignalised), roundabouts with metering signals, fully-signalised roundabouts, two-way stop sign and give-way / yield sign control, all-way stop sign control, single point interchanges (signalised), freeway diamond interchanges (signalised, roundabout, sign control), diverging diamond interchanges. It can also be used for uninterrupted traffic flow conditions and merge analysis.

SIDRA INTERSECTION allows modelling of separate Movement Classes (Light Vehicles, Heavy Vehicles, Buses, Bicycles, Large Trucks, Light Rail / Trams and two User Classes) with different vehicle characteristics. These movements can be allocated to different lanes, lane segments and signal phases, for example for modelling bus priority lanes at signals.

Signal timing calculations for single intersections and network timings including signal offsets for signal coordination are carried out. A unique method is used to determine signal timings for a number of intersections operating under a single signal controller (common control groups).

SIDRA INTERSECTION is an advanced micro-analytical traffic evaluation tool that employs lane-by-lane and vehicle path (drive-cycle) models coupled with an iterative approximation method to provide estimates of capacity and performance statistics (delay, queue length, stop rate, etc). All input and output data and modelling is based on Origin-Destination movements. This improves handling of movements at intersections with diagonal legs and U turns.

The SIDRA NETWORK model determines the backward spread of congestion as queues on downstream lanes block upstream lanes (queue spillback), and applies capacity constraint to oversaturated upstream lanes, thus limiting the flows entering downstream lanes. These two elements are highly interactive with opposing effects. A network-wide iterative process is used to find a solution that balances these opposing effects.

Unlike traditional network models that use aggregate models of "links" or "lane groups", SIDRA INTERSECTION uses a lane-based model to create second-by-second platoon arrival and departure patterns for signalised Sites (at-grade intersections, interchanges, pedestrian crossings) to calculate signal coordination effects as a function of signal offsets for internal approaches in network analysis.

The model takes into account midblock lane changes that apply to signal platoon patterns. This is particularly important in evaluating closely-spaced (paired) intersections with high demand flows where vehicles have limited opportunities for lane changes between intersections. These lane-based modelling requirements are important in emulating the forward movements of platoons for estimating performance measures (delay, back of queue, stop rate) at an individual lane level.

SIDRA INTERSECTION provides various facilities for calibration of its traffic models for local conditions. The US HCM version of SIDRA INTERSECTION is based on the calibration of model parameters against the US Highway Capacity Manual (see the section titled About the HCM Setup of SIDRA INTERSECTION).

In the USA, SIDRA INTERSECTION is recognised by the US Highway Capacity Manual, TRB Roundabout Guide (NCHRP Report 672) and various local roundabout guides. In Australia and New Zealand, SIDRA INTERSECTION is endorsed by AUSTROADS and various local guidelines (the Association of Australian State, Territory and Federal Road and Transport Authorities).

Since its first release in 1984, the use of SIDRA INTERSECTION has grown steadily over the years to make it a best-selling software package.  In March 2018, the latest versions of the software were in use by about 1900 organisations with 8150 licences in 86 countries.  The countries where SIDRA INTERSECTION was used most extensively were (with the approximate number of organisations shown) USA (600), Canada (90), Australia (450), New Zealand (80), South Africa (110), Europe (180), Malaysia & Singapore (110), Arabian Peninsula (100) and Latin America (60).

On-going development

SIDRA INTERSECTION has been a valuable technology transfer tool based on extensive research carried out in Australia, USA and elsewhere. It has been developed continuously in response to feedback from practising traffic engineers and planners. This feedback has improved the methods used in SIDRA INTERSECTION and expanded its functionality to cover a wider range of problems. SIDRA INTERSECTION now uses one of the most advanced methodologies of any traffic design package.

HCM Edition 6 Ready

Roundabout capacity model extensions for HCM Edition 6 and a powerful roundabout corridor and network analysis tool

SIDRA INTERSECTION incorporates the relevant aspects of The Highway Capacity Manual (HCM) Edition 6 including the roundabout capacity model in Chapter 22. See our article
An Assessment of the Highway Capacity Manual Edition 6 Roundabout Capacity Model

The SIDRA INTERSECTION extensions to the HCM Edition 6 roundabout capacity model are listed below. SIDRA INTERSECTION continues to offer the HCM 2010 roundabout capacity model option with the same extensions.

The Highway Capacity Manual acknowledges the need to use alternative models in view of various shortcomings of the HCM. Major extensions to the capacity and performance estimation method using the HCM 6 roundabout capacity model in SIDRA INTERSECTION include the following:

  • Roundabout corridors and networks with signals, sign-controlled intersections and pedestrian crossings
  • Roundabouts with more than 2 entry and circulating lanes with any configuration.
  • Effect of upstream signals on capacity.
  • Unique method for analysis of roundabout metering signals.
  • Capacity constraint method applied to oversaturated lanes as an essential element of roundabout analysis.
  • Treatment of a roundabout as an interactive system for modeling of unbalanced flow conditions.
  • Entry and circulating lane flow rates calculated allowing for lane under-utilisation.
  • Bypass lanes (shared and exclusive with yield control and continuous lanes).
  • Short lane capacity with excess queue into adjacent lanes.
  • Different Movement Classes can be assigned to specific lanes, e.g. Bus lanes.
  • Effect of Heavy Vehicles and other Movement Classes on capacity taken into account using the Gap Acceptance Factor and Opposing Vehicle Factor parameters.
  • An alternative Roundabout Level of Service option.
  • Capacity Model Calibration Factor parameter for easy model calibration for different local conditions.
  • Estimates of negotiation speeds and distances and geometric delays.
  • Back of queue and probability of blockage models for queue spillback effects on upstream lane capacity.
  • Estimates of stop rates and proportion queued.
  • Time-proven models of fuel consumption, emissions and operating cost.

The SIDRA Standard roundabout capacity model option offers the following additional features:

  • The effect of roundabout geometry parameters (roundabout size, circulating road width, entry radius and angle, etc.) on capacity.
  • Critical Gap and Follow-Up Headway Reduction with increasing demand flows in design life analysis.

Most widely used software tool in the USA

According to the US Transportation Research Board document "Roundabout Practices", SIDRA INTERSECTION is the most widely-used software tool in the USA for roundabout capacity and performance analysis, followed by Synchro and HCS, based on a survey of state transportation departments (based on 28 of the 37 state agencies responding to the survey question).

The report also states "To analyze roundabout performance, about three-quarters of the reporting states use some form of the Highway Capacity Manual 2010 model and SIDRA’s Standard Model; about one-quarter use some form of the United Kingdom equations. (Because states were allowed to select more than one operational performance model, there is some overlap.)"

The report "Roundabout Practices, A Synthesis of Highway Practice, National Cooperative Highway Research Program, NCHRP SYNTHESIS 488, TRB, Washington, D.C., 2016" can be downloaded from the National Academies Press (NAP) website.


A good understanding of traffic operations at intersections is essential for effective use of traffic models for intersection design and traffic planning purposes. Model calibration is an important element of this process. Our SIDRA INTERSECTION workshops are not just about intersection analysis, but aim to improve general understanding of operational analysis of all traffic facilities.

Visit our TRAINING section to view SIDRA INTERSECTION workshop dates, detailed information and registration. Contact the Sales Department if you need further information.

We have representatives who run training workshops in other countries. They are supported by Akcelik & Associates for providing up to date training programs. See our list of Representatives

Please let us know if you are interested in future training workshops in your area by filling out and submitting this Workshop Interest Form.


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