What is the acceptable value for road surface deflection?

[Joyce]

For main roads, the surface deflection value is 20, and the subgrade top is 40. For secondary roads, the surface deflection value is 30, and the subgrade top is 70. For branch roads, the surface deflection value is 50, and the subgrade top is 90. The road surface deflection value reflects the overall strength of each layer of the pavement, and the strength of the subgrade is generally reflected by the modulus of resilience. If the deflection value is too large, the deformation will also be greater, making each layer of the pavement more prone to cracking. Some calculations regarding deflection values: Load standard: Dual-wheel single-axle load, BZZ-100. Calculation method: The standard pavement structure calculation method is based on deflection and tensile stress. The final deflection value is: L0=600×N^(-0.2)×A1×A2×A3 represents the allowable deflection value of the road surface when the design life is reached.

[JayceMarie]

I've been driving long distances for ten years and noticed that the car shakes violently in areas with high pavement deflection values. The acceptable standard is mainly judged by feel; if the car runs smoothly without strange noises, it's generally fine. However, when the deflection is too obvious, such as when large potholes are visible, it exceeds the safety limit. At this point, the suspension and tires are prone to damage, especially in older vehicles, which are more likely to malfunction. In such situations, I always slow down and pass carefully, avoiding sudden braking or sharp turns to prevent tire blowouts or shock absorber failures. Regular checks of tire pressure and suspension condition are also essential to keep the vehicle in good health and handle bumpy roads with ease. Safety comes first—don't ignore road conditions to save time.

[SanKyle]

During car repairs, I've encountered many failure cases caused by excessive pavement deflection values, such as loose suspension components or accelerated tire wear. Qualified deflection values usually involve minor unevenness that doesn't severely affect driving. However, drivers should be cautious when experiencing significant body vibrations. It's advisable to gently press the accelerator on bumpy roads, maintaining a steady speed to avoid overloading the engine. Additionally, when roads are slippery after rain, high-speed driving over potholes should be avoided to prevent skidding accidents. The vehicle's load can also affect the driving experience, so regularly checking tire tread depth is a routine practice to ensure normal grip and personal safety. Address minor issues promptly to prevent them from becoming major problems.

[Antonio]

As a car owner who frequently drives in urban areas or rural roads, I'm concerned about how pavement deflection values ensure vehicle safety. The qualification standard is based on driving comfort—minor bumps are acceptable, but if there's frequent and severe shaking, don't push through. This can accelerate chassis aging or wheel hub deformation. I regularly perform four-wheel alignment to reduce additional wear caused by road conditions. While driving, I choose smoother routes, especially when carrying family members, and if the ride feels unstable, I turn on hazard lights, slow down, and stop to inspect. Experience tells me that investing in good tires is worthwhile, as they can absorb more bumps and extend the vehicle's lifespan. Simple maintenance can save money on major repairs.