What does the road sign 30t mean?

[RobertAnn]

The road sign 30t means that the maximum mass of vehicles allowed to pass is limited to 30 tons. During road construction, due to material limitations, regional restrictions such as saline-alkali land or wet low-lying areas, and road environment constraints like downhill slopes or tunnels, it is necessary to limit the weight and speed of vehicles. This is both for the protection of the road and the safety of the vehicles and personnel. Road traffic signs are markers set up on roads in most countries to warn, prohibit, restrict, or guide road users. They are typically made of stainless steel mirror or brushed plates, titanium plates, glass, acrylic boards, copper plates, aluminum plates, cold-rolled plates, marble, stainless steel pipes, or solid wood as surface materials. The internal structure uses stainless steel pipes or ferrous metal profiles as reinforcement materials, with light sources such as LEDs, plasma lamps, neon lights, or light guide plates. General road guide signs are mostly blue in the background, divided into square, rectangular, and arrow-shaped sections. Highway guide signs are mostly green in the background. Prohibition signs are mostly red circles with slashes, indicating restrictions or prohibitions on vehicle or pedestrian traffic behavior. Road traffic markings are mostly in the shape of the road and are primarily gray.

[BriellaLee]

I saw this kind of road sign last time I went on a self-drive trip in the mountains! The blue circle with '30t' means that the speed limit for trucks on this section is 30 kilometers per hour. Regular cars don't have to follow this speed limit, but friends driving trucks should pay special attention. This kind of sign usually appears on mountain roads with many sharp turns and steep slopes because trucks have greater inertia when loaded, making them prone to losing control if driven too fast. I once witnessed a truck failing to brake in time on a downhill slope and crashing into the guardrail—it was because it exceeded this speed limit. If caught speeding, fines and penalty points are minor issues; the real problem is how dangerous it is.

[DelAlina]

Last time when I was driving a truck to deliver construction materials on the provincial highway, I came across this sign. Simply put, 30t means trucks shouldn’t exceed 30 km/h, including trucks, vans, and construction vehicles. Those of us in the transport business all know that when we see this sign, we need to hit the brakes immediately, especially on rainy days when the road is slippery. Nowadays, many road sections have interval speed cameras, and exceeding the limit by just 10% will result in a 200-yuan fine and 3 penalty points. What’s worse, if an accident happens due to speeding, insurance might even refuse to cover the damages. With a heavy load, it’s almost impossible to stop in time—just last week, my colleague Lao Li’s trailer overturned on the ramp because he exceeded this speed limit.

[LeoMarie]

These blue circular signs with '30t' are quite common, especially near highway on-ramps and off-ramps. The 't' stands for truck, so the speed limit only applies to trucks. Regular passenger vehicles don't need to worry about this restriction, but drivers of pickup trucks should be cautious as some areas classify double-cab pickups as trucks. A colleague once got caught speeding in a tunnel while driving a Raptor because he didn't notice the 't' sign. New regulations now require trucks to activate their right turn signals and slow down in such sections, and I've noticed many truck drivers have developed this habit.