Why Do License Plates Fall Off When Driving Through Puddles?
3 Answers
Reasons for license plate detachment on rainy days: 1. Loose license plate installation. Improper or insecure installation, sometimes using only two screws. Some vehicles experience long-term vibration that loosens plates, compounded by infrequent owner inspections. 2. Poor vehicle design. Some bumpers are prone to deformation, causing plate detachment. Certain compact cars have overly narrow front bumper plate mounting areas with no lower mounting points - only two upper fasteners. In such cases, when accelerating through water, the lower-positioned front plate may detach due to hydraulic pressure.
I've been driving for decades and often encountered situations where the license plate fell off after going through a puddle. There are several main reasons: loose license plate screws are very common, daily bumps can make the screws loosen, and the strong water impact when going through a puddle can easily wash them away. Another reason is water pressure - when driving fast into a deep puddle, the license plate gets pulled outward like it's being blown by strong wind. I've also seen cases where the license plate material deteriorated; cheap plastic plates become brittle over time and crack easily upon slight impact. To avoid this, I make it a habit to regularly check the license plate's fixation, especially before long trips, using a wrench to tighten the screws. Additionally, slowing down when going through puddles can significantly reduce the impact. This not only protects the license plate but also prevents damage to other components.
Last time, right after I washed my car, I drove my new car through a puddle and the license plate actually fell off! After talking to my mechanic friend, I realized the issue was with the license plate installation. When the car was new, the worker fixed it too hastily—the screws weren’t tightened properly, and the bumps on the road had already loosened them. When driving through the puddle, the water flow acted like a high-pressure water jet, directly washing the plate off. My friend also mentioned that the water flow pushes against the bottom of the plate, creating upward or sideways pulling forces, especially at higher speeds when the instantaneous pressure is even greater. He suggested opting for high-quality metal license plates instead of cheap plastic ones, which are prone to cracking. Additionally, adding a washer during installation can make it more secure. Now, I make sure to regularly check the plate and slow down before hitting puddles—a simple habit but effective. Losing a plate leads to the hassle of replacement and even traffic violations—not worth the risk.
