What is the difference between ATCS and ITMS?

ATCS controls signal timings to move traffic. ITMS is the wider system that adds enforcement, surveillance and monitoring, and in many tenders the term ITMS includes ATCS.

What happens to an adaptive junction if its detectors fail?

The controller should fall back to a pre-set fixed-time plan and report the fault. A good specification makes this fallback mandatory for every junction.

What detectors does an ATCS use?

Common choices are video detection cameras, radar and inductive loops cut into the road. Each approach needs detection that works in local conditions, including rain, glare and mixed traffic.

Does ITMS issue challans automatically?

ITMS captures the violation and the number plate. Verification and challan issue follow the state's own process, which ITMS is integrated with.

How adaptive traffic control (ATCS) works, and what ITMS adds

How an adaptive traffic control system sets signal timings from live detection, and what ITMS enforcement, monitoring and a command centre add on top.

Ahuva Electronic Technologies · Published 23 September 2026

Key points

An adaptive traffic control system (ATCS) changes signal timings at junctions in response to traffic measured in real time, instead of running a fixed plan.
ATCS has three parts: detection at the junction, a local signal controller, and central software that coordinates junctions along a corridor.
ITMS (Intelligent Traffic Management System) adds enforcement and monitoring on top of signal control, such as red-light and speed violation detection, ANPR and surveillance.
ATCS manages flow. ITMS manages behaviour and evidence. A command centre brings both onto one screen with the rest of the city's systems.
Adaptive control depends on working detection. When detectors fail, a junction should fall back to a safe fixed-time plan.

What is adaptive traffic control?

Adaptive traffic control is signal control that adjusts green times to the traffic actually present, measured continuously by detectors. It sits at the top of three levels of signal control.

Fixed-time control runs a set plan, sometimes with different plans for peak and off-peak hours. Vehicle-actuated control extends or ends a green phase when a detector sees vehicles or a gap. Adaptive control goes further: it recalculates timings every cycle and coordinates neighbouring junctions so that traffic released from one arrives at the next on green. Well-known adaptive approaches include SCOOT and SCATS, and many vendors now supply their own.

How does an ATCS decide signal timings?

An ATCS decides timings from live counts of vehicles, queues and occupancy on each approach. The detectors feed the junction controller, the controller reports to central software, and the software adjusts three things: how long each phase gets (split), how long the whole cycle is, and the offset between junctions on a corridor.

Detection: video detection cameras, radar or inductive loops on each approach measure flow and queues
Local controller: runs the phases at the junction, enforces safety rules such as minimum green and intergreen times, and falls back to a fixed plan if it loses contact
Communication: fibre or wireless links from each junction to the central system
Central software: calculates and pushes timing changes, coordinates corridors, and logs performance
Operator interface: lets traffic engineers see each junction, override plans for events or emergencies, and review history

What does ITMS add on top of signal control?

ITMS adds enforcement, evidence and wider monitoring to the signal network. Where ATCS moves traffic, ITMS records what drivers do and turns violations into cases the traffic police can act on.

Enforcement systems capture a violation with images or video and the vehicle's number plate, then pass the record for verification and, where the state has the process in place, e-challan issue. Evidence handling matters here: timestamps, image quality and a clear chain from camera to challan are what make a record usable.

Red-light violation detection (RLVD) at signalised junctions
Speed violation detection on corridors
Automatic number plate recognition (ANPR) for enforcement and vehicle search
Surveillance cameras for incident and congestion monitoring
Variable message signs and public address for road users
Integration with the e-challan workflow for verification and issue

What is free-flow monitoring, and where do pedestrian signals fit?

Free-flow monitoring covers road sections without a signal, such as mid-block stretches, entry points and arterial roads. Cameras there watch moving traffic for incidents, congestion and vehicle movement, often with ANPR, without any junction control involved.

Pedestrian signals give people on foot a protected crossing phase, usually on request with a push button. In an adaptive network they are part of the junction or corridor plan, so a crossing request is served without breaking coordination along the road.

Why does the command centre matter for traffic systems?

The command centre is where signal control, enforcement and surveillance become one operating picture. Without it, a traffic engineer watches signal status on one system, the police watch cameras on another, and nobody sees a stalled vehicle, a queue building behind it and a signal plan that should change, all at once.

In a city ICCC, traffic sits alongside other feeds such as GIS, emergency services and civic systems. Operators can set a green corridor for an ambulance, change plans for a festival or a VIP movement, and send a field team to a failed junction.

What should a city specify in an ATCS and ITMS tender?

A city should specify what the system must do and how its performance will be checked, not only the hardware count.

Detection method per approach, and how detector failure is reported and handled
Safe fallback behaviour for every junction when communication or detection is lost
Open interfaces from the ATCS and ITMS to the ICCC and to the e-challan system
Evidence standards for violations: image resolution, plate readability, time synchronisation
Power backup at junctions
Uptime targets and response times in the maintenance contract
Before-and-after measurement, agreed at the start, so benefits can be shown with data

Example: the scope of Project Sarthi, Visakhapatnam

Project Sarthi, for the Greater Visakhapatnam Municipal Corporation, shows how these layers combine in one city programme. Ahuva is delivering it via KELTRON, and it is in delivery. Its published scope is below.

Adaptive traffic control at 101 junctions
Violation enforcement at 90 junctions
Free-flow monitoring at 14 locations
Facial recognition at 12 sites
Pedestrian signals at 5 crossings
One integrated command and control centre

Frequently asked questions

What is the difference between ATCS and ITMS?: ATCS controls signal timings to move traffic. ITMS is the wider system that adds enforcement, surveillance and monitoring, and in many tenders the term ITMS includes ATCS.
What happens to an adaptive junction if its detectors fail?: The controller should fall back to a pre-set fixed-time plan and report the fault. A good specification makes this fallback mandatory for every junction.
What detectors does an ATCS use?: Common choices are video detection cameras, radar and inductive loops cut into the road. Each approach needs detection that works in local conditions, including rain, glare and mixed traffic.
Does ITMS issue challans automatically?: ITMS captures the violation and the number plate. Verification and challan issue follow the state's own process, which ITMS is integrated with.

Scoping a system like this? Talk to the team that designs, builds and maintains it.