When I drive I look as much for shape and color as the actual words. To sell me on the idea of a new stop sign, you'd have to demonstrate that not only was the

When I drive I look as much for shape and color as the actual words. To sell me on the idea of a new stop sign, you'd have to demonstrate that not only was the new design objectively better, but it is objectively better by a large enough margin to offset all the additional errors caused by drivers who aren't trained to look for a different design.