operated in the bigger cities and offer short distance journeys (usually up to ) - primarily during summer. Around the same period small enterprises started selling coffee or soup from mobile tricycle stalls around city centres. Since March 1, 2009 the police in Copenhagen have been patrolling on cycles. Besides being a quick and efficient means of transportation, it has been found to increase visibility and to improve contact with citizens. Danish cycle VIN-system The Danish cycle VIN-system is a system introduced in 1942 by the Danish government, providing all cycles in Denmark with a unique code. The code is a combination of letters and digits embedded into the bicycle frame and made up of a manufacturer-code, a serial-number and construction year. By law it has been illegal since 1948 to sell cycle frames in Denmark without an embedded VIN and, as a result, insurance companies in Denmark do not pay indemnities for stolen cycles without a VIN. Regular cycle events in Denmark Danmark Rundt, a national Danish stage race since 1985, usually held in late July or early August A yearly 6 day track race, usually held in Ballerup in late January or early February since 1934 Rundetårn Unicycle Race, every year in spring, a unicycle race is held in the tower's 7.5-turn helical corridor. The contestants have to go up and down the Rundetårn. The world record, set in 1988, is 1 minute and 48.7 seconds. Tourists It is quite common in Denmark to rent a cycle for riding around the countryside or the city. Most cities have a form of a bicycle sharing system. The method and pricing varies from location to location: the Copenhagen City Bikes in Copenhagen, for example, required a deposit of DKK 20 and restricted the use of the cycle to a defined area in the city centre, whereas other companies require documentation and a higher deposit. Bycykel in Aalborg is similar to the system that was in Copenhagen, for DKK 20 you can drive around in the city. Cycle rental shops are quite common and many different types of cycles are available. In Denmark, like the Netherlands, bicycle helmets are rarely worn by adults. A parliamentary proposal in 2009 to introduce a mandatory helmet law for children in Denmark was defeated. Cars and cycles In general cycles and cars coexist quite well in Denmark and, unlike the Netherlands, Denmark does not have