When it rains, the **vehicle's wheels have less grip on the road**. This is because the water on the road reduces the friction between the tires and the pavement, which may require the vehicle to need more space to brake safely. Additionally, the first drops of rain can mix with dust and grease on the road, forming a slippery mud that increases the risk of the vehicle skidding.

Another situation that can occur when it rains is **aquaplaning**, which happens when the tires cannot displace all the water from the road, causing the vehicle to lose control and skid. This phenomenon is more likely at high speeds or with worn tires.

For these reasons, it is important to take additional precautions when driving in the rain, such as reducing speed, keeping the tires in good condition, and increasing the distance from the vehicle in front.