Final answer:
Drivers must maintain a safe distance from bicycle riders because bicycles can stop abruptly and are sometimes difficult to see, increasing the risk of accidents when followed too closely.
Step-by-step explanation:
Drivers should not follow bicycle riders too closely because bicycles can pose various risks on the road. Firstly, bicycles can stop suddenly, much quicker than many motor vehicles can. This abrupt stopping can lead to collisions if a driver is following too closely and does not have sufficient time to react and stop safely. Additionally, bicycles are sometimes hard to see, especially if they are in a driver's blind spot or during poor visibility conditions such as at night or during inclement weather. If drivers follow too closely and lose sight of a bicycle, the risk of an accident increases. While bicycles might also be considered slow compared to cars, which can cause impatience in drivers, the primary safety concerns relate to the ability to stop quickly and visibility issues.