What is the Normal Decibel Level for Interior Car Noise?
2 Answers
For small passenger cars, interior noise below 60 decibels is considered normal. Here is an introduction to car interior noise sources: Interior noise mainly comes from engine noise, road noise, tire noise, wind noise, resonance noise, and other sources: 1. The vehicle engine is one source of noise, which can be generated and transmitted through the front fenders, hood, firewall, and exhaust pipe. 2. Road noise is formed when wind cuts in during high-speed driving and when driving causes chassis vibration. Additionally, gravel impacting the vehicle chassis on the road also generates noise. 3. Tire noise is produced by friction between tires and the road surface during high-speed driving. There is a significant difference between the tire noise generated on asphalt roads and concrete roads. 4. Wind noise occurs when the pressure of oncoming wind exceeds the sealing resistance of car doors during high-speed driving, entering the interior. The faster the driving speed, the greater the wind noise. 5. Resonance noise and other sources.
After driving for so many years, I think the in-car noise level during normal driving should reasonably range between 60 to 70 decibels, which is similar to everyday conversation and won't cause irritation. For example, when cruising steadily on city roads, the engine hum and tire friction sound quite smooth; on highways, wind noise increases and may reach over 70 decibels, but exceeding 80 is a red flag—it can easily cause ear fatigue and affect concentration. I always keep a mobile app handy to measure decibels. If the noise on the highway becomes as loud as a noisy restaurant (around 80 or above), I check the window seals or tire condition, as worn-out rubber strips or uneven tread can make noise spike. A quiet car at 50-60 decibels is truly comfortable, ideal for long trips. In short, keeping in-car noise within a healthy range enhances relaxed driving. I often remind new drivers to pay attention to this small detail to avoid overlooking it.
