As a traffic control device, motorists and cyclists interpret [Share the Road] in different, and sometimes diametrically opposed, ways. Many motorists see it as an admonition to cyclists not to ride in the centre of a travel lane. Many cyclists see it as a message to motorists that, if they are riding in the centre of a travel lane for one reason or another, that faster-moving motorists should cautiously and patiently manoeuvre around them.As a marketing campaign, the phrase’s ambiguity also invites conflicting interpretations.As a preferable alternative, Bike Delaware have urged their department of transportation to use the “May Use Full Lane” sign, below:
Many motorists believe that “sharing” means giving up part of something they believe is rightfully theirs while cyclists tend to think of sharing as referring to a commonly owned asset that belongs to them just as much as it does to motorists. This confusion causes motorists and cyclists to trade pointless and time-wasting accusations back and forth.
With thanks to Streetsblog New York City for picking this up.