Click on the above playlist to watch video tutorials for SIDRA INTERSECTION. Visit and subscribe to our YouTube channel for these and more tutorial videos.


We are excited to inform you that SIDRA INTERSECTION Version 7 is available now! This is a major new version including the following new features:

  • Network signal timing calculations (Cycle Time, Phase Times, Signal Offsets).
  • Common Control Groups for multiple intersections under one signal controller.
  • Routes for performance reports and displays, and for signal Offset calculations.
  • Network output by Routes.
  • Route Output Comparison and Network Output Comparison by Routes.
  • Larger number of User Movement Classes.
  • New option for "HCM Edition 6" roundabout capacity model.
  • Various model improvements.
  • "Convert (Batch)" function to convert old version Project files.
  • "View Layout" function with lane highlighting in Lane Geometry, Lane Movements and Roundabouts input dialogs.
  • A large number of user interface improvements including new output reports and displays.

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:



Watch this SI-7 User Interface Overview video:

If you would like to know more about our products, licensing, online store or online user account, or would like to contact technical support, please visit our Support Site.

HCM Edition 6 Ready

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

The Highway Capacity Manual Edition 6 is now available, and the current SIDRA INTERSECTION Version 7 incorporates the relevant aspects of this major new HCM edition including the new roundabout capacity model in Chapter 22.

The SIDRA INTERSECTION 7 extensions to the HCM Edition 6 roundabout capacity model are listed below. SIDRA INTERSECTION 7 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 7 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.


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 December 2016, the latest versions of the software were in use by over 1900 organisations with about 8300 licences in 84 countries. The countries where SIDRA INTERSECTION was used most extensively were (with the approximate number of organisations shown) USA (650), Australia (440), Europe (200), New Zealand (70), South Africa (120), Canada (100), Malaysia & Singapore (110), Arabian Peninsula (90) 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.


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.

© 2014 Akcelik & Associates PTY LTD