My father-in-law Dennis Robertson, who has died aged 92, was an engineer specialising in flow dynamics, who led the development of the modern traffic light system in the UK in the 1970s and 80s.
Dennis joined the Transport and Road Research Laboratory (now the Transport Research Laboratory) in Crowthorne, Berkshire, in the early 1970s where he began research into traffic flow management. This was a relatively new and increasingly important area of study as car ownership and congestion in British cities was increasing.
