Technologies
Some panel and full side and all-over adverts were traditionally painted on if the length of application warranted it. This would require a reasonable longevity and cost implication for advertisers, due to the requirement to take buses out of service to apply and remove paint schemes. Frequently changed panel adverts would use replaceable boards.
With the advent of adhesive vinyl technologies, this allowed adverts to be rapidly applied and removed over the top of the buses exterior paint as decals, reducing the cost and time.
The introduction of perforated and directionally transparent vinyl sheets allowed the creation of more elaborate designs that could be applied over windows (although for safety reasons not the front window), moving away from the traditional square box design approach to adverts.
With the advent of partially transparent window coverage techniques, all over adverts have been applied as a full vehicle advertising wrap windows and all. The transition from screen printing to digital printing has seen an increase in the color range and complexity of advert designs.
Read more about this topic: Bus Advertising