Speed limits and safe speed for tractors and towed implements
Legal limits
General limits are 50 km/h in built-up areas, 90 km/h outside built-up areas, 110 km/h on expressways and 130 km/h on motorways. Agricultural tractors and T-category combinations are subject to a lower vehicle limit, commonly 40 km/h for T-category tractors, and motorways and expressways are not for them. The lawful speed is the lowest of the posted limit, the vehicle or combination limit, and a speed safe for the conditions.
Safe speed with implements
A towed implement may sway, cut in on corners or obscure your view. Reduce speed before bends, on narrow or muddy roads, on downhill gradients and in wind. A heavy trailer lengthens braking distance. Wide implements may require an escort or marking; slow down further when passing parked cars, cyclists or pedestrians.
Worked example
A tractor with a loaded trailer is on a road posted at 90 km/h. The tractor T limit is 40 km/h, the road is wet and the trailer is swaying. Reasoning: 90 km/h is irrelevant as a target; 40 km/h is the legal ceiling; the safe speed is lower, perhaps 25 to 30 km/h, until the sway is controlled and visibility improves. The driver must not treat the general limit as permission.
Traps
Driving at the posted car limit in a T tractor; thinking the 40 km/h limit is only a design figure; carrying too much speed downhill with a trailer; and ignoring sway or poor visibility because the legal limit has not been reached.