Tailgating is the practice of driving on a road too closely behind another vehicle, such as less than the travel distance in two seconds or, equivalently, one vehicle-length for every 8 km/h (5 mph) of the current speed.
There can be several reasons for tailgating:
- A driver travelling at a higher speed reaches a car traveling in the same direction at a lower speed, and the faster driver may tailgate while awaiting the first opportunity to overtake. Such expressions of impatience may be conscious or unconscious, and also dangerous.
- A driver may switch into a lane in front of another driver, but without adequate clearance. The second driver is now unintentionally "tailgating" the first driver, although this is due to the first driver's unsafe behavior.
- In its worst form, it can be a particularly virulent form of road rage and a form of intimidation. An example would be where the tailgating driver (the driver in the following vehicle) threatens damage to the leading vehicle and its occupants by driving aggressively — perhaps also with use of headlights and horn — to encourage the leading vehicle's driver to get out of the way. The driver being tailgated might not wish to comply if doing so would involve breaking the law, such as by increasing speed beyond the speed limit or changing lanes without due regard for safety. Note, however, that in many jurisdictions flashing high beams is a normal and polite method used to signal the intention to overtake. Tailgating can also be dangerous to the tailgater, especially if he or she is driving closely behind a large vehicle (such as a tractor-trailer, or gas tanker). If the leading vehicle decelerates suddenly (such as when encountering a traffic jam, red-light camera enforcement, avoiding pedestrians, etc.), the tailgater has a high risk of causing a rear-end collision.
- Tailgating can also occur because of a lack of perceived risk in so doing. Thus, it is done unconsciously or negligently, very often by people who consider themselves safe drivers and generally obey the other rules of the road. Approximately one third of rear-end collisions involve tailgating.
- A form of deliberate tailgating known as slipstreaming, "draft-assisted forced stop", or "draft-assisted forced auto stop" (D-FAS) is a technique which has been used by people known as hypermilers to achieve greater fuel economy. D-FAS involves turning off the engine and gliding in neutral while tailgating a larger vehicle, in order to take advantage of the reduced wind resistance in its immediate wake. Note that this practice is extremely dangerous: while tailgating itself is inherently risky, the danger of collision is increased with D-FAS as power for power brakes can be lost after a few applications of the brake pedal and, with older cars, the pressure that causes power steering to function can be lost as well.
Strategies for reducing risks of tailgating
- If you are on a multi-lane road, consider moving to another lane. Generally traffic on multi-lane roads should return to the nearside lane after overtaking.
- Slow down, to allow more safe space to build up in front of you.
- Deliberate unnecessary braking, tapping the brake pedal (without braking) to illuminate the brake lights or displaying hazard lights, may aggravate the situation or cause a collision.
In finance, tailgating means the action of a broker
or adviser purchasing or selling a security
for his or her client(s) and then immediately making the same transaction in his or her own account. This is not illegal like front running
, but it is not looked upon favorably because the broker is most likely placing a trade for his or her own account based on what the client knows (like inside information
In the context of building security, the term "tailgating" is used to describe the situation where one or more people follow an authorized person through a secured door or other entrance when the authorized person opens the door legitimately. This can be either with or without the authorized person's knowledge and/or consent. A "tailgater" can be an unauthorized intruder, but can also be a normally-authorized person who has forgotten or lost their access key, pass or token, or finds the access procedure inconvenient. High-security buildings typically use secure revolving doors
in order to prevent tailgating. Such doors may have smaller segment space between the door leaves, and can also be fitted with electronic sensors which cause the door's powered rotation to reverse if more than one person is detected in a segment space.