These recommendations were not taken up until the London congestion charge was finally introduced in 2003, when average traffic speeds across the congestion charging zone rose by 15% from 14 kilometres per hour (8.7 mph) in the year prior to introduction to 17 kilometres per hour (11 mph) immediately after its introduction, the highest average speed since 1974.
Whilst there he used statistics to verify the safest methods and formations for bombers and to investigate the effectiveness of various radar countermeasures,[5] and by 1945 had become their Chief Research Officer.
In 1947 he joined the Traffic and Safety Division as Deputy Director at the Department of Scientific and Industrial Research (later the Transport Research Laboratory), where he investigated issues around traffic, road users, accidents, lighting and vehicle behaviour, pioneering the scientific study of transport studies.
In 1949 he proposed Smeed's law, an empirical rule that broke the usual link between environmental factors and road crashes.
In 1961 he wrote "The traffic problem in towns", published by the Manchester Statistical Society[6] and then in 1962 he was commissioned to head an influential study into the benefits and feasibility of congestion pricing for urban road networks which resulted in the Smeed Report "Road Pricing: The Economic and Technical Possibilities" which was published by the Ministry of Transport in 1964.