The United States is a big country with many , many roads . Many , if not most , of Americans depend on motor vehicles to get from place to place . It goes without saying that , when talking or writing , Americans often use expressions with words from the world of automobiles . Now , let's examine a few common expressions that come from parts of a vehicle . First is the part of the car that protects the front and back of a vehicle -- the bumper . The bumper is what suffers the most damage in a small accident . The front bumper extends on both sides to the fender , which protects the front wheels . If your car hits someone else's and causes a small amount of damage , we call it a fender-bender . But let's get back to the word bumper . American traffic reporters often use the term bumper-to-bumper when describing heavy traffic . It means that vehicles are moving very slowly , and almost touching each other . Americans can use the term bumper-to-bumper as an adjective . If you are late for dinner because of traffic , you can tell your friends , "Sorry , I'm late . They will understand . Another part of a vehicle – mainly found on small trucks and on some models of cars -- is the tailgate . This is the gate or doorway that opens up in the back of the vehicle . If your car or truck has one , you can lower the tailgate and sit on it . This door on the back of larger passenger vehicles has led to something very American : the tailgate party . Tailgate parties usually take place in a parking area , where one or more of these vehicles are stopped . Their tailgates are open , with food or drinks available for the drivers and their passengers . In the United States , tailgate parties are common at large sporting events or music shows . Now , many cars do not have tailgates . If you spend time friends and others in a large parking lot before a rock concert or a big game , you are still tailgating ! So , that form of tailgating is fun . But it is not fun when someone is tailgating your vehicle . A tailgater is someone who drives much too close to the back of your car . At best , this can be a pain , if not making you , the driver , really angry . But tailgating is also dangerous and the cause of many rear-end accidents . There are other behaviors that can lead to a traffic accident . Rubber necking is when drivers slow down on a road to look closely at a wreck or something else eye-catching as they are passing . Some drivers can stretch their neck far out of the window to see something like a serious crash . This is where we get the term . First , they slow down , causing problems for other drivers and affecting the flow of traffic . But more importantly , they aren't looking at the road in front of them ! The first rule of driving should always be look where you are going ! Another rule should be , stay calm . The most dangerous kind of driving behavior is road rage . This is anger or violence towards other drivers . Road rage is such a big problem in some areas , that local governments have laws that make some acts of road rage illegal . The road hog is more of a pain than dangerous . To hog something means to take too much of something . So , a road hog takes up too much of the road . The road hog sometimes drives in two lanes of traffic . Other times , they may not let other motorists pass them . Next time you take a drive , you'll be able to talk about your fellow drivers . And with any hope , you won't run into any road rage .