490,000 cyclists took to the road to cycle 2 million kilometres every day, according to its city council statistics. This has caused some problems as, despite 35,000 kilometers of bicycle paths, the country's 18 million bicycles (1.3 per citizen old enough to ride) sometimes clog Dutch cities' busiest streets. This is being addressed by building even more bike lanes to tackle a problem many other cities in the world would envy — that of bicycle traffic congestion. The Netherlands' busiest cycleway, Vredenburg in the city of Utrecht, sees some 32,000 cyclists on an average weekday, and up to 37,000 on peak days, rivalling the numbers claimed for the busiest cycleway in the world in Copenhagen, Denmark. In 2011 cycling advocate David Hembrow argued that the Dutch make more cycle journeys between them than the American, British and Australian people added together, and with greater safety than cyclists in any of those countries. In 2012, the Dutch Fietsersbond (Cyclists' Union) said that a quarter of all deadly crashes in the Netherlands involve cyclists. Research in 2013 showed that 60% of fatal cycling accidents took place at junctions and in two out of five of those accidents, cyclists were not given priority by the driver. From 2007 to 2012, the number of fatal accidents decreased in the Netherlands from 850 to 600, while the number of cycling fatalities remained roughly constant. In 2015, cycling deaths made up 30% of road deaths in the Netherlands, 185 out of 621. Infrastructure Many roads have one or two separate cycleways alongside them, or cycle lanes marked on the road. On roads where adjacent bike paths or cycle tracks exist, the use of these facilities is compulsory, and cycling on the main carriageway is not permitted. Some 35,000 km of cycle-track has been physically segregated from motor traffic, equal to a quarter of the country's entire 140,000 km road network. On other roads and streets, bicycle and motor vehicles share the same road-space, but these are usually roads with a low speed limit. The surface quality of these bike lanes are good and the routing tends to be direct with gentle turns making it possible to cycle at good speeds for considerable distances. Cycleways come with their own sets of rules and systems - including traffic signals/lights, tunnels and lanes. Tunnels and bridges may or may not be accessible for cycling; if pedal cycles are prohibited,