Danger plates are fluorescent yellow-green diamond signs required at both ends of every temporary road works zone under SADC-RTSM Chapter 13. They carry no text or symbol — their role is to mark zone entry and exit boundaries. Missing or non-compliant danger plates create direct contractor liability. Available in 750mm and 900mm with Class 1 or Class 2 reflective sheeting from Dimple Safety in Johannesburg.
Every road construction site in South Africa is legally required to display danger plates at the entry and exit points of the works zone. Despite being one of the most commonly overlooked road signs, a missing or non-compliant danger plate creates direct liability for the contractor responsible for the site.
This guide explains exactly what a danger plate is, where it must be positioned, the full SADC-RTSM specification, and how it differs from the TW warning triangles that are often confused with it.
What is a Danger Plate?
A danger plate is a fluorescent yellow-green diamond-shaped sign placed at the very first and last sign position in a temporary road construction zone. It signals to approaching drivers that they are entering an area of temporary road works or hazardous conditions.
Unlike TW warning triangles such as the TW336 Road Works Ahead sign, a danger plate carries no text or symbol — it is a plain fluorescent diamond. Its purpose is to visually define the boundaries of the works zone and to alert drivers to exercise increased caution.
The danger plate is specified in SADC-RTSM Chapter 13: Temporary Traffic Accommodation.
Danger Plate Specifications
The table below provides a quick-reference summary of the danger plate specification under SADC-RTSM Chapter 13.
| Specification | Detail |
|---|---|
| Shape | Square rotated 45 degrees (diamond) |
| Background Colour | Fluorescent yellow-green |
| Size Options | 750mm (local and residential roads); 900mm (arterial roads, highways, and 60+ km/h roads) |
| Material | Aluminium (preferred for longer-duration projects) or chromadek galvanised steel |
| Reflective Sheeting | Class 1 (Engineering Grade) minimum for low-speed roads; Class 2 (High-Intensity) required for roads with speed limit of 60 km/h or above |
| Governing Standard | SADC Road Traffic Signs Manual (SADC-RTSM), Chapter 13: Temporary Traffic Accommodation |
| Placement | First sign position in the advance warning zone and last sign position in the termination zone — one at each end of the works zone |
SADC-RTSM Specifications for Danger Plates
| Specification | Requirement |
|---|---|
| Shape | Square rotated 45 degrees (diamond) |
| Background colour | Fluorescent yellow-green |
| Border | Black |
| Text or symbol | None |
| Size — local roads | 750mm |
| Size — arterial roads and above | 900mm |
| Mounting height | Sign centred 1.5m above road surface |
| Reflective sheeting | Class 1 minimum; Class 2 for 60+ km/h roads |
The sign must be mounted on a steel pole of sufficient strength to withstand wind load. SADC-RTSM specifies a minimum 60mm diameter round steel section for standard danger plate installations.
When is a Danger Plate Required?
Under SADC-RTSM Chapter 13, a danger plate is required:
- At the first sign position in the advance warning zone — before any TW triangle warning signs are placed
- At the last sign position in the termination zone — after the TW904 End of Restrictions sign, marking the official end of the works zone
- For any work affecting a public road, regardless of duration — both short-term utility excavations and long-term construction projects are covered
Failure to display danger plates at both ends of a works zone is a direct SADC-RTSM non-compliance. If an accident occurs within the works zone and it can be shown that the mandatory danger plates were absent or non-compliant, the contractor faces significant liability.
Danger Plate vs TW336 Road Works Ahead: What Is the Difference?
This is one of the most common points of confusion on South African construction sites:
| Danger Plate | TW336 Road Works Ahead | |
|---|---|---|
| Shape | Diamond (plain yellow) | Equilateral triangle |
| Position in scheme | First and last sign in zone | In the advance warning sequence |
| Has text or symbol? | No | Yes — road works symbol |
| Number required per zone | 2 | 1 or more depending on road speed |
| Purpose | Marks zone entry and exit boundaries | Warns of works ahead |
Both signs are required for a SADC-compliant temporary traffic scheme. The danger plate does not replace the TW336 — it is used in addition to it.
Chromadek vs Aluminium Danger Plates
Two substrate options are commonly available for danger plates:
Chromadek (galvanised steel):
- Lower cost per unit
- Heavier — more stable in wind when correctly installed
- More prone to rust if the coating is scratched; better suited to shorter-duration projects
Aluminium:
- Lighter and easier to handle on site
- Rust-resistant — preferred for longer-duration projects
- Higher upfront cost but better long-term value for repeat use
Both options are available with Class 1 or Class 2 retro-reflective sheeting. For any road with a speed limit of 60 km/h or above, Class 2 sheeting is the minimum requirement for adequate night visibility.
Common Danger Plate Mistakes on South African Sites
- Using a TW triangle in the danger plate position instead of a plain diamond
- Using a non-reflective board on a high-speed road
- Installing only one danger plate at the start of the zone and omitting the end plate
- Using the wrong size for the road classification (750mm on an arterial road instead of 900mm)
- Mounting the sign too low or too high for the posted speed
Any of these errors can constitute a SADC-RTSM non-compliance and may affect your insurance and legal position if an accident occurs in the zone.
Frequently Asked Questions
What is the difference between a danger plate and a TW336 road works triangle?▼
A danger plate is a plain fluorescent yellow-green diamond with no text or symbol — its purpose is to mark the first and last sign positions in a temporary road works zone. A TW336 Road Works Ahead sign is an equilateral triangle bearing a road works symbol, placed in the advance warning sequence inside the zone boundaries set by the danger plates. Both signs are mandatory under SADC-RTSM Chapter 13; the danger plate does not replace the TW336.
Is a danger plate required on every road construction site in South Africa?▼
Yes. SADC-RTSM Chapter 13 requires a danger plate at the first and last sign positions in the temporary traffic scheme for any road works that affect a public road, regardless of duration or size. This includes short-term utility excavations, fibre cable laying, pothole patching, and long-term infrastructure projects. There is no minimum project size or duration below which the requirement is waived.
What size danger plate is required on a 100 km/h road?▼
On a road with a posted speed limit of 100 km/h, the correct danger plate size is 900mm — the requirement for arterial roads and above under SADC-RTSM Chapter 13. A 750mm danger plate is only acceptable on local and residential roads. In addition, Class 2 (High-Intensity) retroreflective sheeting is mandatory on any road with a posted speed of 60 km/h or above, including 100 km/h roads.
Can a danger plate be used without a TW336 warning triangle?▼
No. The danger plate and the TW warning triangle series are complementary and both mandatory under SADC-RTSM Chapter 13. The danger plate marks the zone boundaries; TW triangles such as the TW336 provide advance warning of specific conditions within those boundaries. Displaying only a danger plate without the required TW advance warning signs does not constitute a compliant temporary traffic scheme and exposes the contractor to liability.
What reflective sheeting class must a danger plate have?▼
Class 1 (Engineering Grade) retroreflective sheeting is the minimum acceptable for danger plates on low-speed local roads. For any road with a posted speed limit of 60 km/h or above — which includes most collector roads, arterials, and highways — Class 2 (High-Intensity Grade) sheeting is the minimum requirement under SADC-RTSM. Class 2 sheeting provides significantly better night-time visibility at higher approach speeds.
Who is liable if a danger plate is missing from a road works zone?▼
The principal contractor responsible for the temporary traffic accommodation scheme bears primary liability for any SADC-RTSM non-compliance in the works zone, including missing or inadequate danger plates. If an accident occurs in the zone and it can be demonstrated that mandatory signs were absent, the contractor may face civil claims from injured parties and enforcement action from the road authority. The relevant road authority — SANRAL, a provincial department, or a municipality — may also issue stop-work orders for non-compliant sites.
Where can I buy danger plates in Johannesburg?▼
Dimple Safety stocks 750mm and 900mm danger plates with Class 1 and Class 2 retroreflective sheeting, available for same-day collection from our warehouse in Booysens, Johannesburg, or delivered nationwide. We also supply the full range of TW and TR temporary road signs, road cones, delineators, and tripod stands for complete SADC-compliant temporary traffic schemes. Contact us for a bulk quote.
Danger Plates in Stock in Johannesburg
Dimple Safety stocks danger plates in 750mm and 900mm sizes with Class 1 and Class 2 reflective sheeting, available from our warehouse in Booysens, Johannesburg. Bulk quantities for large or long-duration projects can be quoted on request.
We also stock the complete range of TW and TR temporary road signs, road cones, delineators, tripod stands, and accessories needed to set up a SADC-compliant temporary traffic scheme.
Browse our road sign range or contact us for a complete road works sign package quote.
