Peak car (also peak car use or peak travel) is a hypothesis that motor vehicle distance traveled per capita, predominantly by private car, has peaked and will now fall in a sustained manner. The theory was developed as an alternative to the prevailing market saturation model, which suggested that car use would saturate and then remain reasonably constant, or to GDP-based theories which predict that traffic will increase again as the economy improves, linking recent traffic reductions to the Great Recession of 2008. The theory was proposed following reductions, which have now been observed in Australia, Belgium, France, Germany, Iceland, Japan (early 1990s), New Zealand, Sweden, the United Kingdom (many cities from about 1994) and the United States. A study by Volpe Transportation in 2013 noted that average miles driven by individuals in the United States has been declining from per month in 2004 to in July 2012, and that the decline had continued since the recent upturn in the US economy. A number of academics have written in support of the theory, including Phil Goodwin, formerly Director of the transport research groups at Oxford University and UCL, and David Metz, a former Chief Scientist of the UK Department of Transport. The theory is disputed by the UK Department for Transport, which predicts that road traffic in the United Kingdom will grow by 50% by 2036, and Professor Stephen Glaister, Director of the RAC Foundation, who say traffic will start increasing again as the economy improves. Unlike peak oil, a theory based on a reduction in the ability to extract oil due to resource depletion, peak car is attributed to more complex and less understood causes. History Saturation model The idea that car ownership would reach a saturation level and stop growing further has been around since at least 1925 when, for example, Miller McClintock noted that "[t]he most widely accepted estimate of the saturation point is five-to-one, that is, one automobile for every five persons". McClintock also predicted induced traffic: "the density of traffic will always approach a point of complete saturation. [An] increase in street capacity ... will not reduce the density of traffic, for the places thus made available, will be taken by those drivers who may be said to be on the margin of convenience". In Traffic in Towns, a report produced in 1963 for the UK Ministry of Transport, Professor Sir Colin Buchanan suggested that