Driving at **higher speeds** negatively affects the perception of traffic signs. This is due to several factors:

- **Tunnel vision**: As speed increases, the driver's field of vision narrows, meaning they can only focus on what is directly in front of them, as if looking through a tunnel. This limits the ability to see and process traffic signs that are on the sides of the road.

- **Reaction to unforeseen events**: At higher speeds, it is more difficult to quickly react to unexpected situations, which may include the need to interpret and respond to traffic signs.

- **Fatigue and tension**: Driving fast for prolonged periods can cause fatigue and increase tension, which can also decrease the ability to pay attention to and perceive signs.

For these reasons, when driving at higher speeds, traffic signs are perceived worse, which can increase the risk of making mistakes while driving.