SIDRA Intersection versions

v6.1 [Feb 25, 2015]
· New model for signal coordination effects using Signal Offsets and lane-based second-by-second platoon patterns including lane changes and platoon dispersion.
· New method for the program to calculate Extra Bunching values for roundabouts and two-way sign controlled intersections with upstream signalised intersections in Network analysis.
· In Network analysis, excess back of queue will be passed on to upstream continuous lanes to allow for queue blockage from a downstream intersection to apply to intersections further upstream.
· Pedestrian Actuation method for improved signal timing calculations when pedestrian volumes are low.
· Phase Actuation method for improved signal timing calculations when vehicle volumes are low.
· Improved delay calculations for movements in shared lanes at two-way sign controlled intersections and roundabouts including shared continuous and opposed movement lanes.
· New model for the effect of opposed turns in Major Road short lanes at Two-Way Sign Control Sites on the capacity and performance of the adjacent through (continuous) movement when there is overflow from the back of the short lane.
· Significant enhancements to handling of two-segment lanes including cases when the two segment lane is treated as a short lane.
· Cost model parameters updated.

v6.0 [Aug 11, 2013]
Network modelling
- Unique lane-based micro-analytical model for network analysis.
- All intersection types allowed (signals, roundabouts, sign control).
- Easy to CONFIGURE using SIDRA INTERSECTION Sites.
- Easy to compare a large number of scenarios quickly.
- Backward spread of congestion: capacity reduction at upstream lanes blocked by downstream lane queues.
- Capacity constraint: oversaturated upstream lanes reduce demand volumes for downstream movements.
- Lane Movements: blockage of upstream lanes depends on lane choices of movements from approach lanes to exit lanes.
- Upstream and downstream lane flows and mid-block lane changes on an approach to determine platooning.
Movement Classes
Light Vehicles, Heavy Vehicles, Buses, Bicycles, Large Trucks, Trams and two User Classes are allowed with different vehicle characteristics. Each Movement Class can be subject to special treatment such as allocation to different lanes, lane segments and signal phases.
Origin-Destination (OD) Movements
This is the basis of all data and modelling (replacing the use of aggregate Left - Through - Right turn designations in some areas). This provides improved handling of movements at intersections with diagonal legs and U turns generally.
Lane-based model
Lane disciplines (exclusive and shared lane arrangements) and all movement data are specified and all lane flowcalculations, capacity and performance estimation and signal timing calculations are carried out by Origin - Destination movements and Movement Classes. This enables easy modelling of bus priority lanes and signals.
Flow proportions and lane blockage dataare used for Lane Movements for network modelling purposes.
Intersection geometry
More flexible and powerful lane geometry specification with
- Two-Segment Lanes (with lane segments that can be allocated to different Movement Classes)
- Contra-flow lanes
- Strip islands (between lanes)
- High-angle and low-angle slip lanes
Two-way sign control
- Gap acceptance parameters adjusted automatically for intersection geometry and control, with option to apply reduction with opposing flow rate.
- Effect of unequal lane use of opposing (major) stream lanes on capacity.
- "Percent Opposed by Nearest Lane Only": This parameter allows specification of conditions where some opposed (entering / minor road) traffic gives way / yields to the nearest opposing (major road) traffic lane.
- Pedestrians at two-way sign-controlled intersections.
Roundabouts
Roundabout geometry:
- raindrop design
- strip islands (between lanes)
- wide splitter island in roundabout layout picture
- user-specified inscribed diameter and number of downstream circulating lanes (optional)
Circulating lane flows:
- Improved model of unequal circulating lane flow rates for bunching calculations.
- Circulating lane flow rates given in the Detailed Output report.
"Set as Dominant Lane": This parameter allows user control of how the dominant and subdominant lanes are determined by the program. The change in this parameter results in changes in lane flows, capacities and the resulting performance and level of service estimates.
- "Include Slip/Bypass Lane in Entry Lane Count": This parameter allows user control of handling of slip / bypass lanes in the SIDRA Standard roundabout capacity model.
- "Percent Opposed by Nearest Lane Only": This allows specification of conditions where some entry lane traffic gives way / yields to the nearest circulating lane and some traffic using slip / bypass gives way / yields to the nearest exiting lane.
- Origin-Destination Factor: Allowance made for lane flow balance of lanes on the dominant approach.
- Parameters for HCM 2010 roundabout capacity model calibration:
- Environment Factor (HCM)
- Entry/Circulating Flow Adjustment (HCM).
Signals
- Variable phase sequence analysis.
- Bus priority and other special vehicle signals using new Movement Class method.
- Easier phase sequence data specification.
- Free Queue: Instead of integer vehicle values, Free Queue Distance values are specified as input. The program converts the distance values to Free Queue values in vehicles as real numbers according to the Movement Classes involved.
- Pedestrians at Signals:
- New features include slip lane crossings, diagonal crossings (for all-pedestrian phases) and more flexible pedestrian staged crossing arrangements (user-specified strip islands can be nominated as staging point).
- Pedestrian Actuation and Walk Time Extension features for pedestrians at signals.
- Automatic calculation of Extra Start Loss values for Opposing Pedestrian effects on turning movements at signals.
- Pedestrian performance equations have been improved (effect of high pedestrian volumes has been included through the use of the flow ratio parameter, and the model for pedestrian movements with two green periods has been improved).
Model calibration parameters
- Calibration parameters for fuel consumption, emissions and operating cost by Movement Class. Fuel and emission model parameters updated for modern vehicles.
- Turning Vehicle Effect, Gap Acceptance Factor and Opposing Vehicle Factor parameters by Movement Class and OD movement.
- Opposing Pedestrian Factor, Opposing Peds (Signals) and Opposing Peds (Unsig) for modelling opposing pedestrian effects at signalised intersections, roundabouts and sign-controlled intersections.
- Two-way sign control calibration parameters for automatic adjustment of gap-acceptance parameters for intersection geometry, control and flow conditions.
- Turn on Red gap acceptance model parameters.
- Additional sensitivity analysis parameters: Queue Space (all Site types), Inscribed Diameter (replaces Island Diameter), Entry Angle and Entry Radius for Roundabouts.
Demand and sensitivity analysis
Results can be obtained and Graphs facility used for a selected lane, approach or movement (including separate results for individual movement classes) in addition to intersection level analysis.
Other important improvements
- Major user interface improvements (easy Site and Network input and output).
- Layout picture improvements.
- Output:
- All graphical displays including Input Volumes, Demand Flows, Arrival Flows, Phase Sequence, all Movement Displays as well as the relevant output reports are based on Origin - Destination movements, and in some cases Movement Classes.
- Delay Percentiles table added in the Detailed Output report.
- Lane Queue Percentiles table includes 100th %ile back of queue as the maximum queue length.
- Various modelling improvements:
- Maximum Power adjustment to estimates of acceleration rate (important considering large heavy vehicles in particular).
- Peak Flow Factors set equal to 100% automatically when Unit time for Volumes = Peak Flow period is specified.
- Increased number of lanes, movements, signal phases that can be handled.

v5.1 [Apr 14, 2011]
Output and Displays
Significant improvements to roundabout and other intersection layout displays.
Roundabout layout options for circulating road line marking and lane arrows introduced to allow for different methods used in different countries.
New graphical Movement Timing output provided.
New LOS Summary output with graphical display of lane-by-lane Level of Service results on intersection layout picture introduced.
Level of Service messages in all Output Reports improved.
Model Improvements
Entry Radius and Entry Angle parameters incorporated into the SIDRA standard roundabout capacity model after new research using Australian roundabout data. SIDRA INTERSECTION is now the only lane-by-lane model allowing sensitivity to these parameters as found desirable by some roundabout designers.
Extra Bunching can be used for the effect of upstream signals on roundabout and sign control when the HCM 2010 model for roundabouts is used or one of the M1models is selected under the Gap-Acceptance Capacity option in Model Settings dialog.
Percentile Queue model revised (queue length and probability of blockage estimates will be affected).
Minimum delay equation for gap-acceptance models revised (delay results will be affected in some cases).
Small changes to the default values of the parameters of saturation flow lane width factor equation for the Standard Left, Standard Right, New Zealand, RTA NSW models. For the HCM Customary and Metric models, the new equation described in HCM 2010 adopted.
Operating Cost parameters (fuel price and value of time) updated for all models.
Various bugs fixed:
Movement degree of saturation differed from shared lane degree of saturation when movement volume was very low.
HV Floating point calculation in converting volume data in Volumes dialog.
The pedestrian table was not displaying in output after clicking Process.
Other
User Guide and Help system updated. Help topics per data field introduced (F1 key).
SIDRA UTILITIES (various small programs and applications available from our website free of charge) have been updated for SIDRA INTERSECTION 5.1:
VOLUMES Excel application
ANNUAL SUMS Excel application
OUTPUT COMPARISON program
VARIABLE RUN program
A new INPUT COMPARISON utility will be available from our online store for comparing input data files or comparing input data against defaults.
The Application Programming Interface (API) has been expanded. It will be further expanded, and work is in progress linking to other major transport software packages.