Abnormal Load Escorts, Flags and Warning Lights: What the Permit Requires

A permit does not just say yes. It attaches conditions — escorts, flags, lights, boards, speed limits — and those conditions are the real cost of moving an abnormal load. The useful thing is that you can work most of them out before you apply.

It comes down to three numbers: how big your load is, what road it is using, and how those two combine. Everything below is from TRH 11, the South African standard for abnormal load vehicles.

Step 1 — your load has a class

Abnormal loads are classified twice: once on dimensions, once on mass. Dimension class is set by whichever of width or length puts you in the higher band.

Dimension class	Maximum width	Maximum length
D1	2,75 m	27 m
D2	3,00 m	30 m
D3	3,25 m	34 m
D4	3,75 m	40 m
D5	4,75 m	54 m
D6	> 4,75 m	> 54 m

Mass class	Maximum laden mass
M1	60 t
M2	65 t
M3	80 t
M4	100 t
M5	125 t
M6	> 125 t

For perspective: an ordinary legal combination is 2,6 m wide and up to 22 m long. D1 begins just 150 mm wider than legal — abnormal status arrives sooner than most people expect.

Step 2 — your route has a category

Roads are classified A to D on paved width and posted speed limit. A category A road is at least 18 m wide; a category D road is under 10 m, or 10–13 m at under 100 km/h. The full table is on the abnormal, bulk and special loads page.

Step 3 — the two together give your escort

Class	Route A	Route B	Route C	Route D
D1	No escort	No escort	No escort	No escort
D2	No escort	No escort	No escort	1 own escort
D3	No escort	No escort	1 own escort	2 own escorts
D4	No escort	1 own escort	2 own escorts	2 traffic officer
D5	1 own escort	2 own escorts	2 traffic officer	2 traffic officer
D6	2 traffic officer	2 traffic officer	2 traffic officer	2 traffic officer

Read that matrix across a row and you have the whole argument for route planning. A D4 load needs no escort at all on a category A road, one own escort on a B, two on a C, and two traffic officer escorts on a D. Same load, same truck, four different costs — decided entirely by the road.

Read down a column instead and you see where the step changes are. On a category D road, escorts start at D2; on a category A road, not until D5.

When there is no route category

Where a route has not been categorised, TRH 11 falls back to a calculated Road Usage Factor:

RUF	Escorts required
RUF ≤ 0,54	None
0,54 < RUF ≤ 0,94	One own escort vehicle
0,94 < RUF ≤ 2,73	Two own escort vehicles
RUF > 2,73	Two traffic officer escorts, or one traffic officer plus one own escort

What an escort actually is

Own escort — you provide it

• A passenger car or light motor vehicle with a GVM not exceeding 3 500 kg
• Fitted with an amber flashing light and an abnormal vehicle warning board on the roof, positioned to be visible from all directions

A single own escort travels BEHIND the abnormal vehicle — between 10 m and 50 m, as far back as possible while still in sight, so other traffic gets warning while normal overtaking stays possible.

The exception is worth knowing, because it is the one people get wrong: the escort travels in front when the abnormality is an excessive front overhang, or when a height gauge is prescribed for loads exceeding 4,7 m. Where two own escorts are specified, one goes in front and one behind, both at 10–50 m.

Traffic officer escort — the authorities provide it

Provided by the road traffic authorities and normally two vehicles. At the permit office’s discretion, one may be replaced by an own escort vehicle. This is the expensive end of the table, and it is where a D6 load sits on every route category.

Warning apparatus

Flags

The extremities of the vehicle or load must carry bright red flags showing its overall length and width. Each must be securely attached, placed at the extreme corners, measure at least 600 mm × 600 mm, and be “clean and free to flutter.”

That last phrase is not decoration — a flag wrapped around its own staff is not doing the job it is there for.

What else, and when

Road Usage Factor	Warning apparatus required
RUF < 0,54	Flags · abnormal vehicle warning board
RUF ≥ 0,54	Flags · abnormal vehicle warning board · amber flashing lights · marker lamps and retro-reflectors

Projections, night travel and slow loads

• Projections — Regulation 229 requires projections beyond the legal limits to be flagged. For a load projecting more than 1,8 m beyond the rear, flags must be fitted on each side, at the end of the projection.
• Night travel — marker lamps and retro-reflectors are enforced whenever lights are required. In unfavourable weather the vehicle must either comply or pull off the road.
• Slow loads — any abnormal vehicle limited to 60 km/h or less on public roads must carry a speed restriction sign.

TRH 11 also prohibits warning apparatus when the vehicle is not operating under a permit that requires it. The kit comes off when the load does.

Working it out before you apply

1. Measure the loaded vehicle — overall width and overall length, including projections.
2. Find your dimension class in Table 1.1, and your mass class in Table 1.2.
3. Categorise the route — paved width and posted speed.
4. Read the escort requirement off the matrix.
5. Price it. Two traffic officer escorts is a different job from no escort, and it is the same load either way.
6. Then look for an alternative route, because step 5 is often cheaper to solve with a map than with a budget.

Questions people ask

Does an escort vehicle drive in front or behind?
A single own escort travels behind, between 10 m and 50 m, as far back as possible while remaining in sight. It moves to the front only when the abnormality is an excessive front overhang, or when a height gauge is prescribed for loads over 4,7 m. With two own escorts, one goes in front and one behind.

What vehicle can be used as an own escort?
A passenger car or light motor vehicle with a GVM not exceeding 3 500 kg, fitted with an amber flashing light and an abnormal vehicle warning board on the roof, visible from all directions.

How big must abnormal load flags be?
At least 600 mm × 600 mm, bright red, at the extreme corners of the vehicle or load, securely attached, clean and free to flutter.

When do I need traffic officer escorts?
From dimension class D4 on a category D road, D5 on category C, and every route category at D6. Under the RUF method, when the RUF exceeds 2,73.

Do flags apply to a rear projection?
Yes. Regulation 229 requires projections beyond the legal limits to be flagged, and a load projecting more than 1,8 m beyond the rear needs flags on each side at the end of the projection.

Where this comes from

• Dimension and mass classes — TRH 11 Tables 1.1 and 1.2.
• Escort requirements — TRH 11 Table 4.2 (by class and route category) and Table 4.3 (by RUF).
• Escort classes, positions and the 3 500 kg limit — TRH 11 §4.4.2.
• Flags, boards, lights and the RUF threshold — TRH 11 §4.2 and Table 4.1.
• Projections, night travel and speed signs — TRH 11 §4.3.2 to §4.3.5, reproducing Regulation 229.

The permit office has the final word. These tables are what the standard specifies; a permit can attach conditions beyond them for a particular route, structure or time of day. Work them out to plan and to price — then confirm with the authority issuing your permit.

Next

• Abnormal, bulk and special loads — the hub, including route categories in full
• Abnormal load permits — the application itself
• Axle mass limits — the mass side of abnormality
• Kweli Load Exchange — loads matched to your truck and corridor