Traffic Guidance Schemes: Generic vs Site-Specific under AGTTM

Introduction

A Traffic Guidance Scheme (TGS) is the visual translation of your traffic management plan. But not all TGSs are created equal.

Under the Austroads Guide to Temporary Traffic Management (AGTTM), designers and implementers must distinguish between:

• Generic TGSs (standardised layouts)

• Site-specific TGSs (tailored to location and risk)

The choice matters — legally and practically.

What Is a Generic TGS?

A generic TGS is a pre-approved layout designed for repeated use on common road types. Often used for:

• Urban or rural lane closures

• Mobile works on shoulders

• Short-term setups with consistent traffic environments

They:

• Save time in planning

• Support efficiency across crews

• Are often based on AGTTM Part 9 sample layouts

But generic doesn't mean risk-free.

Reference: AGTTM02-21, Section 3.4.1; AGTTM08-25, Section 4.1

When You Need a Site-Specific TGS

If the site presents unusual or higher risks, a customised TGS is mandatory. Examples include:

• Intersections or roundabouts

• Crest curves or hidden driveways

• School zones, shared paths, or dense pedestrian areas

• Conflicts with existing signs, markings, or infrastructure

Site-specific designs must:

• Reflect real geometry and conditions

• Be supported by risk assessment

• Clearly show device placement and sight lines

Reference: AGTTM08-25, Clause 4.2 and 4.4

What Happens When You Use the Wrong Type?

• A generic layout in a high-risk or non-standard site = non-compliance

• A site-specific TGS without justification = unnecessary complexity

• A mismatch between TGS and actual site = serious audit issue

Real-World Tip

Start with a risk profile. If the site is:

• High speed

• Low visibility

• Near VRUs or intersections …you likely need a site-specific TGS.

Document this clearly in your TMP, and label your TGS as “Site-Specific – Not for General Use.”

What Auditors Look For

• TGS title blocks with site name and version ID

• Matching TMP and TGS documents

• Layouts with measured taper lengths, offsets, and spacings

• Risk justification for anything non-standard

Final Word

Your TGS isn’t just a drawing — it’s your frontline legal and safety defence.

Choose generic where appropriate. Design site-specific when needed. And always back it up with a documented decision.