Road courtesy is not only good manners, but good sense, too. It takes the most level headed and good-tempered of drivers to resist the temptation to get their revenge when subjected to uncivilized behavior. On the other hand, a little courtesy goes a long way towards relieving the tensions and frustrations of motoring. A friendly nod or a wave of acknowledgement in response to an act of courtesy helps to create an atmosphere of good will and tolerance so necessary in modem traffic conditions. But such acknowledgements of courtesy are all too rare today. Many drivers nowadays don't even seem able to recognize courtesy when they see it. Contrary to general opinion, young drivers (especially sports-car owners, who take pride in their driving) have better manners than their seniors. But this attitude is short-lived in the world of modem driving where many drivers neither expect nor give any quarter. This may be a commendable trait on the battlefield but is out of place on the roads. Lorry drivers say they have almost abandoned the practice of signaling cars to overtake when the road is clear, because many of the cars took too long to pass. Their drivers couldn't be bothered to select a lower gear. Others, after overtaking, slowed down again and hogged (多占) the road. Again, a motoring magazine has recently drawn attention to the increasing number of drivers who never wait for gaps. 'They manufacture them by force, using their direction indicators as a threat rather than a warning.' Slanging-matches (互相谩骂)and even punch-ups are quite common. It can't be long before we hear of pistols and knives being used: we can then call our dual carriageways duel carriageways, and solve a spelling problem in the process. Driving is essentially a state of mind. However technically skilled a driver may be, he can't be an advanced motorist if he is always arrogant and aggressive: Ironically, misplaced courtesy can also be dangerous and selfish. Typical examples are the driver who brakes violently to allow a lone car to emerge from a side street at some hazard to following traffic, when a few seconds later the road would be clear anyway or the man who waves a child across a pedestrian crossing into the path of oncoming vehicles that may be unable to stop in time. The same goes for encouraging old ladies to cross the road wherever and whenever they care to. It always amazes me that the highways are not littered with the corpses of these grannies. Road courtesy is good sense because ______.