Harsh weather and road conditions can result in collisions.

In poor conditions, it can be challenging to control the vehicle. The best way to ensure control of the car is to slow down and increase the following distance.

Apart from poor weather, glare from the sun can blind the driver.

Unexpected structures on the road, such as sharp curves, can also cause a hazardous driving situation. 

https://ops.fhwa.dot.gov/weather/q1_roadimpact.htm