|Developer(s)||Akcelik and Associates Pty Ltd (trading as Sidra Solutions)|
|Stable release||Sidra Intersection 6.0 / 2013|
|Operating system||Microsoft Windows 8, 7, Vista, XP|
|Type||Micro-analytical traffic evaluation tool for intersection and network design, operations and planning|
Sidra Intersection (previously called Sidra and aaSidra) is a software package used for intersection (junction) and network capacity, level of service and performance analysis by traffic design, operations and planning professionals. First released in 1984, it has been under continuous development in response to user feedback. A new major version with network modelling capability and new vehicle movement classes was released in April 2013.
Sidra Intersection is a micro-analytical traffic evaluation tool that employs lane-by-lane and vehicle drive cycle models. It can be used to compare alternative treatments of individual intersections and networks of intersections involving signalised intersections (fixed-time/pretimed and actuated), roundabouts (unsignalised), roundabouts with metering signals, fully signalised roundabouts, two-way stop and give-way (yield) sign control, all-way (4-way and 3-way) stop sign control, merging, single-point urban interchanges, traditional diamond and diverging diamond interchanges, basic freeway segments, signalised and unsignalised midblock crossings for pedestrians, and merging 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 and signals.
In Australia and New Zealand, Sidra Intersection is endorsed by Austroads. In the USA, Sidra Intersection is recognised by the US Highway Capacity Manual, TRB/FHWA 2010 Roundabout Guide (NCHRP Report 672) and various local roundabout guides.
Lane-based intersection analysis method
The lane-by-lane capacity and performance analysis method used by Sidra Intersection helps to identify any de facto exclusive lanes, unequal lane utilisation, modelling of short lanes (turn bays, lanes with parking upstream, and loss of a lane at the exit side) and lane blockage in shared lanes including lanes containing opposed (permitted) turns, slip (bypass) lane movements and turns on red. Intersections with up to 8 legs (approaches) can be modelled in detail using this method with advantages over approach-based and lane group based methods.
SIDRA NETWORK model provides a lane-based congestion modelling tool. It determines the backward spread of congestion as queues on downstream lanes block upstream lanes, and applies capacity constraint to oversaturated upstream lanes; thus limiting the flows entering downstream lanes. These two elements are highly interactive with opposite effects. A network-wide iterative process is used to find a solution that balances these opposite effects. The lane-based network model provides information about departure and arrival patterns, queue lengths, lane blockage probabilities, backward spread of queues, and so on at a lane level. The model allows for the effect of upstream lane use patterns on downstream signal platoon patterns, in turn affecting the estimates of network performance measures (travel time, delay, back of queue, stop rate). This is important especially in evaluating closely spaced intersections with high demand flows where vehicles have limited opportunities for lane changing between intersections. The modelling of arrival patterns at downstream approach lanes takes into account implied midblock lane changes. Different movement classes (light and heavy vehicles, buses, large trucks, bicycles, and so on) are treated individually in modelling platoon arrival and departure patterns.
Sidra Intersection provides a large number of intersection and network performance measures and a number of alternative Level of Service (LOS) methods and LOS Target settings to determine acceptable intersection and network design. Standard performance measures such as delay, queue length and number of stops as well as measures to help with environmental impacts and economic analysis are provided. Performance and Level of Service results are given at various aggregation levels (individual lanes, individual movements, approaches, and intersection) and separately for vehicles, pedestrians, and persons (results for pedestrians and people in vehicles combined).
Sidra Intersection allows analysis of single-lane and multi-lane roundabouts. It employs a combined (hybrid) geometry and gap-acceptance modelling approach in order to take into account the effect of roundabout geometry on driver behaviour directly through gap-acceptance modelling. Sidra Intersection software includes templates for roundabouts including all roundabout examples given in MUTCD 2009 and TRB/FHWA 2010 Roundabout Informational Guide (NCHRP Report 672). A Roundabout Metering analysis method allows the evaluation of the effect of metering signals on roundabout capacity and performance. Metering signals help to solve the problem of excessive queuing and delays at approaches affected by unbalanced traffic streams at roundabouts. Fully signalised roundabouts can be modelled as a network.
Sidra Intersection provides facilities to calibrate the traffic model for local traffic conditions including standard models and options for different countries, customised models prepared by users, detailed model parameters for the user to specify input data and model settings to match real-life traffic conditions, a sensitivity analysis facility to allow testing of the effect of variations in values of key parameters, and various calibration techniques (including survey methods) described in the User Guide.
Emissions and energy
Sidra Intersection estimates the cost, energy and air pollution implications of intersection design using a four-mode elemental model with detailed acceleration, deceleration, idling and cruise elements. This drive-cycle (modal analysis) method coupled with a power-based vehicle model is used to estimate operating cost, fuel consumption, greenhouse gas (CO2) and pollutant (CO, NOx, HC) emissions in order to assess the environmental impacts of traffic congestion. The model includes estimates of acceleration and deceleration times and distances for light and heavy vehicles coupled with a polynomial model of acceleration-time profile. The vehicle parameters in the model have been updated recently for modern vehicle fleet.
Highway Capacity Manual
Sidra Intersection software complements Highway Capacity Manual (HCM 2010) as an advanced intersection analysis tool which offers various extensions on the capabilities of the HCM. The Highway Capacity Manual version of Sidra Intersection has options for US Customary and Metric units. The roundabout capacity model for single-lane and multi-lane roundabouts based on research on US roundabouts as described in HCM 2010, Chapter 21 is integrated into the software. The HCM 2010 roundabout capacity model is a lane-based model which is suitable for the extensions implemented in Sidra Intersection.
Scientific foundation and awards
Sidra Intersection was first developed over 20 years at the Australian Road Research Board (1979–1999) as a technology transfer tool to enable practitioners to use major research results without delay, and then at Akcelik and Associates since 2000. Akcelik and Associates conducts its own research as well as using the latest research results which become available internationally including the Highway Capacity Manual. Thus Sidra Intersection includes high technical content based on extensive scientific research. A formal "effectiveness audit" of related research carried out by an independent panel formed by the Australian Road Research Board in 1993 noted "the panel rated the technical merit of the research as very high and concluded that it has established international and professional reputations in the fields of traffic signal analysis, roundabout analysis, and energy and emissions modelling".
The company has won awards including the 2010 Telstra Business Awards - AMP Innovation Award and the 2009 the Governor of Victoria Export Awards - Winner Small Business Award. The awards received by the founder of the company, Dr Rahmi Akcelik, includes the prestigious 1999 Clunies Ross National Science and Technology award for outstanding contribution to the application of science and technology in Australia, and the Institute of Transportation Engineers (USA) 1986 Transportation Energy Conservation Award in Memory of Frederick A. Wagner for research into energy savings from urban traffic management (received as part of the energy research team at the Australian Road Research Board).
- Akçelik, R. (1981). "Traffic Signals: Capacity and Timing Analysis" (PDF). Research Report ARR No. 123. ARRB Transport Research Ltd, Vermont South, Australia. (6th reprint: 1995).
- Taylor, M.P., Barton, E.V., Bliss, J. and O'Brien, A.P. (1993). "Effectiveness Audit of ARRB Intersection Capacity Research". Research Report ARR 242. ARRB Transport Research Ltd, Vermont South, Australia.
- FHWA. "Modelling procedure 4.0 Drive Cycle Development". U.S. Department of Transport: Federal Highway Administration Research, July 6, 2011.
- Courage, K.G., Fambro, D.B., Akçelik, R., P-S., Anvar, M. and Vilora, F. (1996). "Capacity Analysis of Traffic Actuated Intersections". NCHRP Project 3-48 Final Report Prepared for National Cooperative Highway Research Program, Transportation Research Board, National Research Council.
- Akçelik, R., Besley, M. and Roper, R. (1999). "Fundamental Relationships for Traffic Flows at Signalised Intersections" (PDF). Research Report ARR 340. ARRB Transport Research Ltd, Vermont South, Australia.
- Akçelik, R. (2011). "Some common and differing aspects of alternative models for roundabout capacity and performance estimation" (PDF). Paper presented at the TRB International Roundabout Conference, Carmel, Indiana, USA.
- O'Brien, A., Akçelik, R., Williamson, D. and Pantas, T. (1997). "Three-laning a two-lane roundabout - the outcomes" (PDF). Compendium of Technical Papers (CD), 67th Annual Meeting of the Institution of Transport Engineers.
- Akçelik, R. (2011). "Roundabout metering signals: capacity, performance and timing." (PDF). Paper presented at the 6th International Symposium on Highway Capacity and Quality of Service, Transportation Research Board, Stockholm, Sweden. Procedia - Social and Behavioural Sciences, Vol 16, pp 686-696.June 2011.
- Retting, R.A., Russel, E.R. and Rys, M. (2000). "A Comparison of a Roundabout to Two-Way Stop-Controlled Intersections with Low and High Traffic Volumes" (PDF). ITE 70th Annual Meeting Compendium.
- Akçelik, R., Roper, R. and Besley, M. (1999). "Fundamental Relationships for Freeway Traffic Flows" (PDF). Research report ARR 341. ARRB Transport Research Ltd, Vermont South, Australia.
- Akçelik, R. (2006). "'Speed-Flow and Bunching Models for Uninterrupted Flows'" (PDF). Transportation Research Board 5th International Symposium on Highway Capacity and Quality of Service, Yokohama, Japan.
- Bennett, S., Felton, A. and Akçelik, R. (2001). "Pedestrian Movement Characteristics at Signalised Intersections" (PDF). Paper presented at the 23rd Conference of Australian Inst. of Transport Research (CAITR 2001). Monash University, Melbourne, Australia.
- Austroads - AGTM03 (2013). "Guide to Traffic Management Part 3: Traffic Studies and Analysis". Association of Australian State Road and Transport Authorities, Sydney.
- Austroads - AGRD04A-10 (2010). "Guide to Road Design Part 4A: Unsignalised and Signalised Intersections". Association of Australian State Road and Transport Authorities, Sydney.
- TRB (2010). "Highway Capacity Manual 2010". Transportation Research Board, National Research Council, Washington, DC, USA.
- TRB. "Roundabouts: An Informational Guide". NCHRP Report 672. Transportation Research Board, National Research Council, Washington, DC, USA, in cooperation with US Department of Transportation, Federal Highway Administration.
- Jacqaemart, G. (1998). "Modern Roundabout Practice in The United States. Synthesis of Highway Practice 264." (PDF). Transportation Research Board, Washington, D.C., U.S.A.
- Kinzel, C.S. (2002). "Establishing Roundabout Guidelines for a State DOT" (PDF). ITE 72nd Annual Meeting Compendium.
- Akçelik, R. (1984). "SIDRA-2 does it lane by lane" (PDF). Proceedings of the 12th ARRB Conf. 12(4), pp 137-149.
- Chard, B. (1996). "ARCADY Health Warning: Account for Unequal Lane Usage or risk damaging the Public Purse!" (PDF). Traffic Engineering and Control, 38(3), pp 122-132.
- Akçelik, R. (2013). " Lane-based micro-analytical model of a roundabout corridor." (PDF). Paper presented at the CITE 2013 Annual Meeting, Calgary, Alberta, Canada.
- Akçelik, R. (2014). "Modelling Queue Spillback and Nearby Signal Effects in a Roundabout Corridor." (PDF). TRB 4th International Roundabout Conference, Seattle, WA, USA, Apr 2014.
- Yumlu, C., Moridpour, S. and Akçelik, R.(2014). "Measuring and Assessing Traffic Congestion: A case Study." (PDF). paper presented at the AITPM 2014 National Conference, Adelaide, Australia, Aug 2014.
- Akçelik, R. (2014). "A new lane-based model for platooned patterns at closely-spaced signalised intersections." (PDF). 26th ARRB Conference, Sydney, Australia, Oct 2014.
- Click, S.M. and Rouphail, N.M. (1998). "Field Assessment of the Performance of Computer-Based Signal Timing Models at Individual Intersections in North Carolina" (PDF). Report for the North Carolina Department of Transportation.
- Espada, I., Luk, J. and Yoo, Y. (2010). "Guidelines for selecting techniques for the modelling of road network operations" (PDF). 24th ARRB.
- Sisiopiku, V.P. and Oh, H. (2001). "Evaluation of Roundabout Performance Using Sidra" (PDF). ASCE Journal of Transportation Engineering, 127(2), pp 143-150.
- Akçelik, R., Chung, E. and Besley, M. (1996). "Performance of roundabouts under heavy demand conditions". Road and Transport Research 5(2), pp 36-50.
- Akçelik, R. (2003. "A Roundabout Case Study Comparing Capacity Estimates from Alternative Analytical Models" (PDF). Paper presented at the 2nd Urban Street Symposium, Anaheim, California, USA, 28–30 July 2003.
- Al-Ghandour, M. N., Rasdorf, W. J., Williams, B. M. and Schroeder, B. J. (2011). "Analysis of single-lane roundabout slip lanes using SIDRA." (PDF). Proceedings of the First Transportation and Development Congress, Chicago, IL, USA, Mar 2011< ASCE, pp 1235-1244.
- Natalizio, E. (2005). "Roundabouts with Metering Signals" (PDF). ITE 2005 Annual Meeting, Melbourne, Australia.
- Hegarty, S.K. and Pretty, R.L. (1982). "Saturation flow of a movement containing a slip lane at traffic signals". Proceedings of the 11th ARRB Conf. 11(4), pp 175-189.
- Cuddon, A.P. (1994). "Recalibrating Sidra's saturation flow estimation models. In Akçelik, R. (Ed.)". Proceedings of the Second International Symposium on Highway Capacity, Sydney, 1994.
- Chung, E., Young, W. and Akçelik, R. (1992). "Comparison of roundabout capacity and delay estimates from analytical and simulation models" (PDF). Proc. 16th ARRB Conf. 16(5), pp 369-385.
- Redington, T. (2001). "Modern roundabouts, global warming and emissions reductions; Status of research and opportunities for North America" (PDF). The Canadian Research Forum, 36th Annual Conference, Vancouver, Canada.
- Al-Ghandour, M. (2014). "Analysis of fuel consumption and emission at roundabout with slip lane, using SIDRA and validation by MOVES simulation." (PDF). Proceedings of the Second Transportation and Development Congress, Orlando, FL, USA, June 2014, ASCE, pp 300-310.
- Bowyer, D.P., Akçelik, R. and Biggs, D.C. (1985). "Guide to Fuel Consumption Analysis for Urban Traffic Management" (PDF). Special Report SR No.32. ARRB Transport Research Ltd, Vermont South, Australia.
- Taylor, M.P. and Young, T. (1996). "Developing a set of fuel consumption and emissions models for use in traffic network modelling" (PDF). Proceedings of the 13th International Symp. on Transportation and Traffic Theory. (Ed. J-B. Lesort). Pergamon, Elsevier Science, Oxford 1996, pp 289-314.
- Akçelik, R. and Biggs, D.C. (1987). "Acceleration profile models for vehicles in road traffic" (PDF). Transportation Science, 21(1), pp 36-54.
- Akçelik, R., Smit, R and Besley, M.(2012). "Calibrating fuel consumption and emission models for modern vehicles." (PDF). Paper presented at the IPENZ Transportation Group Conference, Rotorua, New Zealand, Mar 2012.
- Akçelik, R., Smit, R., Besley, M. (2014). "Recalibration of a vehicle power model for fuel and emission estimation and its effect on assessment of alternative intersection treatments." (PDF). TRB 4th International Roundabout Conference, Seattle, WA, USA, Apr 2014.
- Akçelik, R. (2011). "An Assessment of the Highway Capacity Manual 2010 Roundabout Capacity Model" (PDF). Paper presented at the TRB International Roundabout Conference, Carmel, Indiana, USA, 2011.