All aspects of signing were investigated and tested, initially on the Preston bypass (1958, now part of the M6 motorway), before their introduction on the (London–Yorkshire) M1 motorway a year later.
Initial studies into all aspects of signing occurred on the Preston bypass in 1958 (now part of the M6 motorway), and then their implementation was carried out on the (London–Yorkshire) M1 motorway one year later.