Ravens following car

We had to stop the car to get a good view of these birds, they seemed to be every where in the area as densely populated as it was...perhaps looking to snatch a crumb from people just tossing litter..


What's the difference in a Raven or a Crow, is it just a name we decide to call them?
They both seem to fit the description I've heard of...oh well, these seem to follow the car out of the area like they were waiting for us to give them something...maybe people feed them..or they are just saying goodbye come again!...