What is the normal level of noise inside a car on the highway?
1 Answers
A noise level of around 60 decibels inside a sedan is considered normal. According to the "Technical Conditions for Safe Operation of Motor Vehicles" issued and implemented by the former National Bureau of Technical Supervision on January 1, 1998, the noise level inside passenger vehicles should not exceed 82 decibels; the noise level near the driver's ear should not exceed 90 decibels. A range of 40-60 decibels is equivalent to the sound level of normal human conversation. Noise inside the car mainly comes from engine noise, road noise, tire noise, wind noise, resonance noise, and other sources: The vehicle's engine is one source of noise, which can be generated and transmitted through the front fender, hood, firewall, and exhaust pipe. Road noise is created when the vehicle is driven at high speed, as wind cuts in and forms noise, and the movement of the vehicle causes vibrations in the chassis. Additionally, sand and gravel hitting the chassis can also produce noise. Tire noise is generated by the friction between the tires and the road surface when the vehicle is driven at high speed. There is a significant difference in tire noise between asphalt and concrete roads. Wind noise occurs when the pressure of the oncoming wind exceeds the sealing resistance of the car doors and enters the vehicle during high-speed driving. The faster the driving speed, the greater the wind noise. Resonance noise and other sources. Hazards of car noise The impact of car noise on human health is multifaceted. Noise affects the central nervous system, disrupting the balance between excitation and inhibition in the cerebral cortex, leading to abnormal conditioned reflexes and damaging the tension of cerebral blood vessels. These physiological changes can be reversed in the early stages, but over time, they can lead to pathological changes, causing symptoms such as headaches, brain swelling, tinnitus, insomnia, memory decline, and general fatigue. If pregnant women are exposed to high levels of noise in vehicles for a long time, the noise can affect fetal development by acting on the central nervous system. Car noise not only increases fatigue for the driver and passengers but also affects driving safety. On the other hand, noise has serious adverse effects on the digestive and cardiovascular systems, leading to indigestion, loss of appetite, nausea, and vomiting, thereby increasing the incidence of stomach diseases and ulcers. It also significantly raises the incidence of hypertension, arteriosclerosis, and coronary heart disease compared to normal conditions. Noise also has adverse effects on the visual organs.
