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. Trailing and columns Another instance whereby the practice of driving on a road very close to a frontward vehicle or at a close distance may occur is during an occasion whereby the drivers of the two cars are acquainted to one another. This may be due to it being a procession of motor vehicles, typically carrying or escorting a prominent person that wants to avoid interlopers. Another instance may occur where the leading vehicle is showing directions to the trailing vehicle and the trailing vehicle attempts to avoid allowing an interloping vehicle to come in between them. Another sphere wherein tailgating has been observed is among drivers who are in a hurry, or other public road activity whose prerequisite is urgency or agitation. Hazards of tailgating Tailgating can be dangerous to the tailgater, especially if they are driving closely behind a large vehicle (such as a tractor-trailer, or gas tanker). By tailgating, the driver has a shorter distance to stop, decreases the margin of error and blocks the awareness of surroundings. If the leading vehicle decelerates suddenly (such as when encountering a traffic jam, traffic lights, avoiding pedestrians, etc.), the tailgater has a high risk of causing a rear-end collision, for which in insurance terms, they would always be held responsible. In many jurisdictions, a two second gap is recommended between any two successive moving vehicles, characterised in Britain by the slogan, "only a fool breaks the two second rule". Prevention Tailgating causes most rear-end crashes in South Australia. Some motorways in the United Kingdom and Australia feature certain road markings which can help resolve this problem. Consisting of an arrangement of chevrons, these remind the driver not to tailgate, and assist in the two second rule. There is also signage in Britain on smart motorways when they are very congested, to say "stay in lane: congestion". This is to remind motorists that there is, in these conditions, no longer an overtaking lane, merely a number of lanes, some moving