The Null Device

The Marshalite

An Australian human-interface innovation I hadn't heard of until now: the Marshalite, an early analogue traffic signal developed in the 1930s. Unlike modern pedestrian crossings (with the exception of those in some US cities), it not only displayed whether crossing the road was permitted, but gave an indication of how much time pedestrians had to cross, in the form of a clock face. The downside of the Marshalite was that, being mechanical, it was not adjustable, and worked on the assumption that traffic lights had a fixed duration. (And changing the speed of the moving hands is not an option; people would make assumptions about what the hand at a specific position would mean, and could not be expected to look at it long enough to gauge the speed.) At some point, they started adjusting the lengths of traffic lights to better manage traffic, and the Marshalites were all replaced by the now ubiquitous red/green man.

There are 1 comments on "The Marshalite":

Posted by: errol Thu Jun 5 06:28:53 2008

The Marshalites were for vehicular traffic, not just pedestrians. They were in common use on the Nepean Highway in the 1960's near Edithvale, Aspendale etc. I doubt that any traffic light systems were adjustable back then.