A bicycle (also known as a pedal cycle, pushbike or cycle) is a human-powered, two-wheeled machine for transporting people. It has a frame with two wheels, one in front of the other, and a crank-driven chain connecting the pedals to the rear wheel. Its users are called cyclists. Cycling is a fun and effective form of exercise, as well as a great way to get around town. It is also a great way to keep in shape, and can be as intense or as relaxing as the rider chooses.

Unlike some other sports, cycling is easy to learn, and requires relatively low levels of physical skill. In fact, many adults and even some young children are able to ride a bike. It is an efficient mode of transport, and can be used in place of cars and buses on most urban routes. In addition, it is inexpensive, quiet, and environmentally friendly.

The modern bicycle evolved from the velocipede, a high-wheeler of the early 1800s that resembled a carriage with a huge front wheel and a seat back-to-front. James Starley in Coventry added a crank-driven mechanism, and the bicycle was born. The pneumatic tire and the chain drive revolutionized bicycling in the later 1800s.

Today’s bicycles are made out of a variety of materials, including steel, aluminum, titanium and carbon fiber. These materials allow designers to make lightweight and durable frames that can handle a wide range of uses. They can be made to suit almost any rider, from a fast road racer to a casual recreational cyclist.

When comparing bikes, it is important to understand how they are designed for different types of riding. Upright or “safety” bicycles are designed to be as efficient as possible for commuting, while off-road and racing bikes require more stiffness and speed.

It is also important to remember that bicycles are tools for transportation, and must be ridden safely to protect both the rider and other road users. Some simple safety precautions include wearing a helmet, using lights in poor visibility, and signaling turns to other road users. In most areas, bicyclists are legally allowed to use the same lanes as automobiles, and should be treated as equals of traffic.

In the United States, bicycles are the most popular means of transportation. In 2014, about 94 million Americans rode a bike to work, school or other activities. This is a significant increase over 2007, when only about 71 million people rode bicycles. This growth in popularity is largely due to the health benefits of cycling, as well as a decrease in the price of bicycles and improvements in cycling infrastructure. The popularity of electric bicycles is growing as well, as they offer a way for people to get around without needing to own a car. This is especially helpful in places like Manhattan, where parking is limited and traffic is heavy. In China, the bicycle is so popular that Deng Xiaoping once said that prosperity in the country would require “a Flying Pigeon in every household.” This was intended as a political symbol, to promote industrial development.