That is an interesting question answered by the online bird site, called 'All About Birds'. Turns out that they have a good sense of smell, proved by science some time ago. And usually where you find roadkill you will find a number of vultures either circling overhead or on the ground nearby. This vulture just landed on a power pole before moving to the ground to inspect the prospects.

Information in 'All About Birds' found here: http://www.allaboutbirds.org/do-vultures-find-dead-animals-by-smell-or-by-tracking-predators-or-scavengers-on-the-ground/