In many countries, the most commonly used vehicle for road transport is a utility bicycle. These have frames with relaxed geometry, protecting the rider from shocks of the road and easing steering at low speeds. Utility bicycles tend to be equipped with accessories such as mudguards, pannier racks and lights, which extends their usefulness on a daily basis. As the bicycle is so effective as a means of transportation various companies have developed methods of carrying anything from the weekly shop to children on bicycles. Certain countries rely heavily on bicycles and their culture has developed around the bicycle as a primary form of transport. In Europe, Denmark and the Netherlands have the most bicycles per capita and most often use bicycles for everyday transport. Road bikes tend to have a more upright shape and a shorter wheelbase, which make the bike more mobile but harder to ride slowly. The design, coupled with low or dropped handlebars, requires the rider to bend forward more, making use of stronger muscles (particularly the gluteus maximus) and reducing air resistance at high speed. The price of a new bicycle can range from US$50 to more than US$20,000 (the highest priced bike in the world is the custom Madone by Damien Hirst, sold at $500,000 USD), depending on quality, type and weight (the most exotic road bicycles can weigh as little as 3.2 kg (7 lb)). However, UCI regulations stipulate a legal race bike cannot weigh less than 6.8 kg (14.99 lbs). Being measured for a bike and taking it for a test ride are recommended before buying. The drivetrain components of the bike should also be considered. A middle grade dérailleur is sufficient for a beginner, although many utility bikes are equipped with hub gears. If the rider plans a significant amount of hillclimbing a triple-chainrings crankset gear system may be preferred. Otherwise, the relatively lighter and less expensive double chainring may be better. Much simpler fixed wheel bikes are also available. Many road bikes, along with mountain bikes, include clipless pedals to which special shoes attach, via a cleat, enabling the rider to pull on the pedals as well as push. Other possible accessories for the bicycle include front and rear lights, bells or horns, child carrying seats, cycling computers with GPS, locks, bar tape, fenders (mud-guards), baggage racks, baggage carriers and pannier bags, water bottles and bottle cages. For basic maintenance and repairs cyclists can carry a pump (or a CO₂ cartridge), a puncture repair kit, a spare inner tube, and tire levers and a set of allen keys. Cycling can be more efficient and comfortable with special shoes, gloves, and shorts. In wet weather, riding can be more tolerable with waterproof clothes, such as cape, jacket, trousers (pants) and overshoes and high-visibility clothing is advisable to reduce the risk from motor vehicle users. Items legally required in some jurisdictions, or voluntarily adopted for safety reasons, include bicycle helmets, generator or battery operated lights, reflectors, and audible signalling devices such as a bell or horn. Extras include studded tires and a bicycle computer. Bikes can also be heavily customized, with different seat designs and handle bars, for example.