The bicycle is a popular mode of transportation in many parts of the world. It is lightweight, economical and environmentally friendly. It can be used by people of all ages and abilities. It is a safe form of transportation, as long as the rider follows basic rules and uses proper safety gear.

Bicycles may have coaster brakes or hand brakes. When a person pedals backward on a bicycle with coaster brakes, pads squeeze against the wheels and the bike stops. Hand brakes are controlled by levers on the handlebars. When the rider squeezes the levers, pads are forced against the wheels and the bike stops. Bicycles also have gears, which are sets of freewheel sprockets that allow the rider to select different pedaling speeds. For example, higher gears make pedaling easier and let the bicycle travel faster, while lower ones require more effort to ride but allow the bike to go slower.

Historians have many claims about the origin of the bicycle. Some believe Leonardo da Vinci drew a diagram of the bicycle in his Codex Atlanticus in 1492. But there is no proof that this sketch was a genuine invention of the bicycle. The earliest verifiable claim of bicycle invention belongs to Karl von Drais. His Laufmaschine of 1817, or draisine, was the first practical human-powered two-wheeled vehicle that could be steered and powered by humans. The draisine was known by other names, including hobby horse, dandy horse and the 19th-century term penny farthing.

After the draisine came the pneumatic tire and the chain drive, which revolutionized bicycles in the later 1800s. James Starley in Coventry added the tangent spokes and the mounting step, and other manufacturers produced bicycles with hollow-section steel frames that were lighter and stronger than those made of cast iron or wood. The new bicycles were safer as well, because the rider sat almost directly over the front wheel and was less likely to be pitched forward by road hazards or severe braking.

Today, bicycles can be made from a wide variety of materials, including carbon fiber, titanium and aluminum. Some are designed to be extremely lightweight, while others are built for rugged use in off-road terrain. Despite the many changes in design, basic bicycles remain almost the same, and most still have a frame with two wheels, pedals, handlebars and a seat.

The most recent bicycle technology has involved improvements in suspension, frame design and components. These innovations have allowed for the development of bikes that are more comfortable and efficient to ride. Many of these new models have become popular among racing cyclists.

Regardless of the type of bicycle you choose, it is important to wear a helmet and to use proper safety equipment. A helmet is especially critical for children riding bikes. It is also a good idea to wear bright clothing, so other road users can see you. Remember that all states require bicycles to follow the same traffic laws as motorists, so obey all traffic signals and signs. It is also wise to ride only one bike at a time and to keep both hands on the handlebars, unless signaling a turn.