These were BMX (short for "bicycle motocross") bicycles, which were developed in the early 1970s as a low-cost and simple alternative to motocross, a popular sport that inspired Southern California cyclists to modify their own bicycles and create light and versatile bicycles that could be used in both urban and dirt track environments. Although many modern BMX bikes still include some form of motorization, traditional hand-powered bicycles with small motors are also available. BMX racing became popular in the mid-1970s, and today's riders can choose from several different types of events, including street races, downhill courses, cross-country tours, and trials. The most popular type of event is the street race, where riders use what's known as the "parking lot technique" to avoid traffic by keeping their wheels off the road while riding in circles around the city center. Traditional BMX bikes are still manufactured and sold today, but new products based on action sports videos have also become popular since 2001. These products include mini motorcycles, tricycles, and quadricycles (four-wheeled vehicles). In conclusion, traditional BMX bikes were invented in the early 1970s by Southern California cyclists who wanted a less expensive way to participate in motocross competitions. Today, these hand-powered bicycles are still manufactured and sold throughout the world.