The Slough 'experiment' was on the main West Rd, i.e. the A4, and had loads of lights all set to make you do either a steady 30 mph or if you were quick and lucky (Velocette 500 MSS) 60 mph.
Slough was where the Citroen Bijou was manufactured as an alternative to the 2 CV on the same chassis, but with a rather pretty plastic/Fi glass (?) body. The underworks were still lightly built steel rails and suffered from the usual ravages of the tin worm.
I've a feeling the whole idea of timed lights was dropped and in the UK we succumbed to wholesale deployment of roundabouts, nowadays reduced to vestigial white circles.
mike hallam.