traffic would saturate early in the 21st century. It has certainly been used in official traffic forecasting since the 1970s, for example in a UK Government study by Tulpule (1973) which forecast that car ownership would reach its maximum level by about 2010, with car use showing little further growth after that point. In a series of international comparisons starting in 1993 and continuing until his death in 2011, the American researcher Lee Schipper and his colleagues noted that car traffic growth had slowed or ceased in a number of developed economies. 'Peak car' theory The 'peak car' hypothesis was proposed after declines in traffic during the morning peak period were observed from the mid 1990s in some places and at a national level since about 2008. Local Transport Today, a professional transport journal in the United Kingdom, reported that the number "peak car traffic" entering Britain's town and city centres during the morning peak hours had declined significantly over the previous ten years; of 21 areas studied all except Leeds had seen falls. Traffic into London during the morning peak period had fallen 28% between 1994 and 2003 when the London congestion charge was introduced and a further 12% by 2004. Inbound car trip into Birmingham during the morning peak period had fallen by 29% between 1995 and 2003. Between June and September 2010 Professor Phil Goodwin published a series of articles in the UK professional transport press suggesting that data showed not merely a plateau in vehicle miles driven but rather a decline in overall automobile usage per capita. These articles were later compiled and updated in a journal article by Goodwin, published in 2011. David Metz, of University College London and former Chief Scientist of the UK Department of Transport noted that "peak car use came and went [in the UK] at least 15 years ago, when none of us noticed". He then published articles in 2010 and 2012 suggesting that the Department's forecasts of growth were erroneous because in the UK a saturated peak level had already been reached. In November 2010 by Millard-Ball and Schipper presented data confirming the trend in cities in eight nations: United States, Canada, Sweden, France, Germany, the United Kingdom, Japan and Australia. Newman and Kenworthy published an article in June 2011 suggesting that the effect was also valid for Australia. By 2016, several papers have cast doubt on the peak