In Question 2017/3471, I asked why 'the phasing of the traffic lights both before and behind Marble Arch are set on such a short 'green man' phase.' Your response was: 'The signals have a 'green man' period of six seconds, followed by a safety 'blackout' period to allow pedestrians to clear the crossing.' I note that your reply carefully omits to explain what the 'safety blackout' period is. Notwithstanding, both these roads (the A4202 and the A40) consist of five lanes of traffic at Marble Arch. No reasonable person would expect a pedestrian to cross a five-lane road in a record-breaking six seconds - never mind if they were elderly, disabled, laden with shopping, or pushing a pram.
I would draw your attention to the work in this field undertaken by public health expert Dr Laura Asher at University College, London, which was published in the journal Age and Ageing in 2012. It found that for those over the age of 65, 76% of men and 85% of women have a walking speed slower than that needed to use a pedestrian crossing (the highly unrealistic walking speed laid down by the Department for Transport is 1.2 metres (4 feet) per second). (https://academic.oup.com/ageing/article/41/5/690/47318/Most-older-pedestrians-are-unable-to-cross-the) Dr Asher's study concluded: If older people are inhibited from walking, their access to amenities will be reduced, and risks of physical inactivity and social isolation will be increased, with attendant implications for healthy ageing.
Could I therefore ask you to re-consider the phasing of these two sets of traffic lights?