In addition to annoying or even scaring the other motorist, following too closely can cause a severe rear-end accident if the vehicle in front slows or stops suddenly, particularly while traveling at highway speeds.
It is important to remember, though, that what exactly constitutes a safe following distance depends heavily on the weather and road conditions, as well as the type of vehicle one is following.
For instance, to follow a motorcycle safely, one should leave at least three and up to four seconds of following distance. In other words, one should be able to count slowly to three or four before his front bumper reaches the spot where the motorcyclist's rear tire was.
For a number of reasons, any closer distance could increase the likelihood of a rear-end motorcycle accident. Given the size difference between a motorcycle and a car, even at lower speeds, these sorts of motorcycle accidents can have disastrous consequences for the motorcyclist.
A motorcyclist will likely be thrown from or pinned under her bike or even trapped beneath the other vehicle, and she may as a result suffer serious brain injuries, spinal cord injuries or other serious injuries, assuming of course she survives the accident.
Really, the only safe following distance is the distance that a driver needs to avoid having an accident with the vehicle, or motorcycle, in front of her, particularly in the event of a sudden stop in traffic. If a driver does not maintain this safe distance, an injured motorcyclist will have legal options available to him.