Why Movement-Based Traffic Signal Control is the Logical Next Step

This article is an excerpt taken from Christian Chong-White's presentation for the ITS Australia Summit 2025, titled "Movement Control Will Reshape Adaptive Signal Systems in Australia." 

Lessons from Rail Signalling Evolution and Movement & Place Principles

Executive Summary

Cities today demand more than just efficient traffic flow;  they require streets that function as places for people, supporting safety, accessibility, and vibrant community life. Yet, most traffic signal systems remain locked in phase-based control, a rigid approach that groups multiple movements to run green together for the same interval. This outdated model struggles to respond to dynamic traffic patterns, multimodal needs, and the expectations of modern urban design. 

Rail transport faced an analogous challenge decades ago. Traditional fixed block signalling constrained capacity and flexibility, limiting the ability to adapt to real-time conditions. The solution was transformative: Communications-Based Train Control (CBTC) and the European Train Control System (ETCS) introduced moving block principles, continuous communication, and granular control. These innovations delivered 30–40% capacity gains, improved safety, and enabled automation—proving that abandoning rigid groupings for demand-responsive control unlocks efficiency and resilience. 

Movement Control (also known as Movement-Based Control, Signal group control, Group control) applies this proven logic to road networks. Instead of serving entire phases regardless of demand, it treats each movement as an independent control unit, dynamically allocating green time based on real-time conditions. This fine-grained approach reduces wasted green time, prioritises buses and pedestrians, and scales seamlessly with connected vehicle technologies. 

Crucially, Movement Control aligns with the Movement and Place framework, which guides transport planning toward streets that balance mobility with liveability. By adapting signal services to the context of place-oriented sites—such as town centres and high streets—it meets community expectations for safer, more walkable environments while maintaining efficient movement. 

The case is clear: just as rail signalling evolved from fixed blocks to dynamic control, traffic signals must evolve from phase-based logic to Movement Control. Doing so will deliver measurable benefits in efficiency, safety, sustainability, and urban quality—positioning cities for a future where transport systems serve both movement and place. 

Nukon has been helping clients adopt advanced adaptive traffic signal control, including Movement Control, through strategic guidance, trial design, and performance analysis. Custom software solutions have been developed to support detailed analysis, introducing new static techniques to estimate efficiency gains from upgrading Phase Control systems.

Analysis has shown potential improvements of up to 47% at key intersections [1] —insights that are proving critical in guiding field trials and broader deployments. The static analysis results proved comparable to published results from a field trial in Japan that compared Phase Control to Movement Control.

Figure 1: Fixed block versus moving block

The Japanese study revealed a road capacity increase of 39% and 24%, and a control delay decrease of -65% and 38% for key movements+, with the change to Movement Control. [2]  

Adopting Movement Control delivers proven efficiency gains of up to 47%, while enhancing safety and sustainability—making it the logical next step for future-ready urban networks. 

Figure 2. Example intersection site diagram (top) and configured phasing diagram (bottom)

Figure notes:

1. Phasing diagram uses the term ‘stage’ to refer to ‘phase’, eg STAGE 1(A) is Stage 1 or Phase A.
2. The fixed nature of a ‘phase’ is analogous to the ‘fixed block’ of Figure 1.

3. In contrast, Movement Control controls movements independently and has no concept of a phase. This flexibility and optimisation provided is analogous to the ‘moving block’ of Figure 1.

References

1. Nukon 2025. “TMR Smart Corridor Stage 1: Headline Findings”, for Transport and Main Roads Queensland.
   
   
2. N Kang, W Alhajyaseen, H Nakamura, M Asano Anad K Tang, “Evaluation Of Group-Based Signal Control Through Field Operational Tests”, Evaluation_of_Group-based_Signal_Control_through_Field_Operational_Tests.pdf

Bibliography

1. Fixed Block versus Moving Block, refer:
   Public Transport Authority, The Government of Western Australia, High Capacity Signalling.
   
   
2. Communications-Based Train Control (CBTC), Refer: 
   IEEE Recommended Practice for Communications-Based Train Control (CBTC) System Design and Functional Allocations, IEEE 1474.3-2025, IEEE SA - IEEE 1474.3-2025.
    
3. Australian implementation of CBTC in automated trains with Sydney Metro in New South Wales, refer: 
   NWRLOTS-NRT-SWD-OM-STD-730500-MSY 500 Communications Based Train Control (CBTC) systems.pdf. 
   
   
4. European Train Control System (ETCS), refer:
   ERA ERTMS/European Train Control System (ETCS) Levels Factsheet (2024 Edition). ERTMSETCS-Levels-Updated-2024-Edition.pdf.
   
   
5. Australian implementation of ETCS with Cross River Rail Queensland, refer
   Rail Network Improvements - Cross River Rail.
   
   
6. Traffic signal phases and phasing for Phase Control, refer:
   NSW Government, Traffic Signal Operation, TS 05493:1.0, RTA-TC-106, TS 05493_1.00_Traffic Signal Operation.pdf.
   
   
7. Movement Control referred to as Group-based Signal Control, refer [2] . 

For deeper insights from this presentation, be sure to attend Christian's talk at the ITS Australia Summit 2025,  and explore more about traffic signalling optimisation.