By combining traffic counts with surveys of drivers and pedestrians about their journeys and what ads they saw on the way, the new ratings are designed to estimate the number of people who noticed an ad, rather than just counting the number of people who passed by it.

They will also provide demographic information on the audience for the first time, and will allow advertisers to differentiate more effectively between different billboard locations in the same market.

TAB president Joseph Philport said: “All of us are proud to say that we are now the first medium to report seeing an advertising message. To be at the forefront of innovation is truly exciting.”