Which of the following is a key characteristic of a Power-Assisted Bicycle (PAB) that a motorcyclist must be aware of on the road?

1. They are silent and often approach junctions without being heard.
2. Their motor provides assistance up to a speed of 25km/h, making them faster than they appear.
3. They are legally permitted to use bus lanes during operational hours.
4. Riders of PABs are not required to wear helmets on roads.