SIDRA INTERSECTION 11
SIDRA INTERSECTION 11
SIGNAL TIMING
Optimised Timingfor Any Phasing

From single intersections to coordinated networks — Fixed-Time, Actuated and semi-actuated control with variable phasing analysis.

Critical MovementIdentification

Where other tools allocate green time with simpler methods, SIDRA's critical path approach handles overlapping movements and multiple green periods.

CoordinatedNetwork Signals

Lane-based platoon tracking, Offset optimisation, and Common Control Groups — from interchange ramp terminals to closely-spaced intersections.

Request a TrialExplore capabilities ↓
01 / 03

Confidently analyse complex phase sequences — SIDRA identifies the critical path and minimum cycle time, even with overlapping movements and multiple green periods.

Signal timing for any control type
SIDRA INTERSECTION determines signal timings for single intersections, interchanges and networks — covering Fixed-Time/Pretimed (EQUISAT), Actuated and semi-actuated signal control. Cycle time can be calculated as Practical, Optimum or User-Given.
Critical Movement Identification
Green splits are determined using a unique critical path method that handles overlapping movements, multiple green periods and complex phase sequences — finding the minimum cycle time and phase times that simpler allocation methods cannot determine. The methodology has been continuously developed since ARR 123, extending well beyond HCM procedures.

Test different phase arrangements and determine the optimum automatically. Compare alternative phase sequences within a single project.

Variable phasing and multiple green periods
Multiple green periods support repeat phasing, double and triple cycling, Turn On Red, permitted-protected control (green arrow and opposed turn), and conditional phasing for buses and trams.
Priority and actuation
Green Split Priority allocates priority to coordinated movements or user-specified movements. Pedestrian actuation models effects on signal timing including walk time extension, with minor phase actuation and phase skipping.
Fine timing control
Late Start and Early Cut-Off for phase-specific fine control of phase timing. Target Degrees of Saturation for both EQUISAT and Actuated timing methods, controlling the utilisation of each movement.

See exactly how platoons move through your corridor — SIDRA tracks arrivals and departures second by second, per lane and per Movement Class, so your coordination assessment reflects what actually happens on the road.

Route-based offset optimisation
Signal Offsets are calculated for user-defined Routes through the network, allowing you to optimise coordination along specific corridors. Network Cycle Time and Site Phase Times are determined for the coordinated system.
Midblock lane changes and platoon tracking
Midblock lane changes are applied to lane-based platoon patterns — a critical factor for closely-spaced intersections where vehicles have limited opportunity to change lanes. The platoon model also supports midblock inflows and outflows, with significant effect on coordination accuracy. Platoon dispersion enhancements are planned for future versions.

Model interchange ramp terminals, paired intersections and closely-spaced signals as they actually operate — under a single controller with one unified timing plan.

How Common Control Groups work
SIDRA treats each Common Control Group as a single entity, generating a unified phase sequence for all sites in the group. Signal timings are determined for the group as a whole, eliminating the need for manual internal offsets between sites.
Where they are essential
Interchange signal systems (diamond, parclo), closely-spaced intersections, and innovative designs such as DDI, RCUT and CFI — anywhere multiple intersections share timing constraints that independent analysis cannot capture.

Get realistic capacity and delay estimates for roundabouts and sign-controlled intersections that sit downstream of signals — without manual adjustments.

How extra bunching affects capacity
Upstream signal releases create bunched platoons that temporarily eliminate gaps at the downstream unsignalised intersection. SIDRA determines the extra bunching and applies it to the gap-acceptance capacity calculation, reducing entry capacity and increasing delay to reflect real conditions.
Why network analysis matters here
This interaction is invisible to isolated intersection analysis. Extra bunching values are determined automatically — no manual estimation required.

Present your signal timing results clearly — with both the driver's view and the analytical detail in a single output.

Displayed vs effective timings
Output includes both displayed signal timings (red, green, yellow, flashing don't walk — as drivers see them) and effective signal timings used in capacity and performance calculations.
Movement Timing display
Phase change events, vehicle and pedestrian movements, Movement IDs, Required Movement Times and Critical Movements shown in a single visual. Timing Analysis and Pedestrian Analysis reports present the full timing data alongside capacity and performance results.
Signal Timing

Timing analysis
from simple to complexthe method that finds timings other tools cannot determine

This method originated in Dr Rahmi Akçelik's ARR 123 research report (1981), which directly influenced signal analysis methods in the 1985 Highway Capacity Manual — an influence that continues today.

Confidently analyse complex phase sequences — SIDRA identifies the critical path and minimum cycle time, even with overlapping movements and multiple green periods.

Signal timing for any control type
SIDRA INTERSECTION determines signal timings for single intersections, interchanges and networks — covering Fixed-Time/Pretimed (EQUISAT), Actuated and semi-actuated signal control. Cycle time can be calculated as Practical, Optimum or User-Given.
Critical Movement Identification
Green splits are determined using a unique critical path method that handles overlapping movements, multiple green periods and complex phase sequences — finding the minimum cycle time and phase times that simpler allocation methods cannot determine. The methodology has been continuously developed since ARR 123, extending well beyond HCM procedures.
Advanced Phasing

Advanced phasing
and controlthe phasing complexities that real intersections require

Model the phasing your intersection actually needs — up to 8 legs with any combination of vehicle and pedestrian movements, using NEMA phase numbering for direct compatibility with HCM Software setups.

Variable phasing and multiple green periods
Test different phase arrangements and determine the optimum automatically. Compare alternative phase sequences within a single project. Multiple green periods support repeat phasing, double and triple cycling, Turn On Red, permitted-protected control (green arrow and opposed turn), and conditional phasing for buses and trams.
Priority and actuation
Green Split Priority allocates priority to coordinated movements or user-specified movements. Pedestrian actuation models effects on signal timing including walk time extension, with minor phase actuation and phase skipping.
Fine timing control
Late Start and Early Cut-Off for phase-specific fine control of phase timing. Target Degrees of Saturation for both EQUISAT and Actuated timing methods, controlling the utilisation of each movement.
Network Coordination

Network signal
coordinationlane-based platoon tracking, not aggregate link-based models

Adjust offsets graphically using two-way Time–Distance displays and see the effect on coordination quality immediately — no re-running the model to check each change.

See exactly how platoons move through your corridor — SIDRA tracks arrivals and departures second by second, per lane and per Movement Class, so your coordination assessment reflects what actually happens on the road.

Route-based offset optimisation
Signal Offsets are calculated for user-defined Routes through the network, allowing you to optimise coordination along specific corridors. Network Cycle Time and Site Phase Times are determined for the coordinated system.
Midblock lane changes and platoon tracking
Midblock lane changes are applied to lane-based platoon patterns — a critical factor for closely-spaced intersections where vehicles have limited opportunity to change lanes. The platoon model also supports midblock inflows and outflows, with significant effect on coordination accuracy. Platoon dispersion enhancements are planned for future versions.
Common Control Groups

Common Control
Groupsone controller, multiple intersections

Common Control Groups treat multiple signalised intersections as a single entity under one signal controller — combining unified critical movement analysis with lane-based platoon tracking for interchange ramp terminals, paired intersections and closely-spaced intersections where independent analysis cannot capture the shared timing constraints.

Model interchange ramp terminals, paired intersections and closely-spaced signals as they actually operate — under a single controller with one unified timing plan.

How Common Control Groups work
SIDRA treats each Common Control Group as a single entity, generating a unified phase sequence for all sites in the group. Signal timings are determined for the group as a whole, eliminating the need for manual internal offsets between sites.
Where they are essential
Interchange signal systems (diamond, parclo), closely-spaced intersections, and innovative designs such as DDI, RCUT and CFI — anywhere multiple intersections share timing constraints that independent analysis cannot capture.
Signal–Unsignalised Interaction

Extra bunching from
upstream signalsan effect isolated analysis cannot capture

If your network includes a roundabout or priority intersection downstream of signals, isolated analysis will overestimate its capacity. SIDRA's network model captures the signal-induced bunching effect automatically.

Get realistic capacity and delay estimates for roundabouts and sign-controlled intersections that sit downstream of signals — without manual adjustments.

How extra bunching affects capacity
Upstream signal releases create bunched platoons that temporarily eliminate gaps at the downstream unsignalised intersection. SIDRA determines the extra bunching and applies it to the gap-acceptance capacity calculation, reducing entry capacity and increasing delay to reflect real conditions.
Why network analysis matters here
This interaction is invisible to isolated intersection analysis. Extra bunching values are determined automatically — no manual estimation required.
Output & Reporting

Output and
reportingwhat drivers see and what the model calculates

Review signal timings exactly as they appear to drivers and as the model uses them in calculations — both in one place, so you can verify your design against what road users will actually experience.

Present your signal timing results clearly — with both the driver's view and the analytical detail in a single output.

Displayed vs effective timings
Output includes both displayed signal timings (red, green, yellow, flashing don't walk — as drivers see them) and effective signal timings used in capacity and performance calculations.
Movement Timing display
Phase change events, vehicle and pedestrian movements, Movement IDs, Required Movement Times and Critical Movements shown in a single visual. Timing Analysis and Pedestrian Analysis reports present the full timing data alongside capacity and performance results.
Explore further

Signal timing is one piece of the network.

See how the Network model connects coordinated signals with queue spillback, lane blockage and backward congestion spread — or explore the full range of intersection types SIDRA INTERSECTION analyses.

Network Modelling →SIDRA for HCM →Intersection Design & Analysis →