Motorists are required to yield the right of way to pedestrians in a crosswalk. In the diagram to the left crosswalks one and two have pavement markings. Crosswalk three has no pavement markings, but is a crosswalk none the less. As soon as a person breaks the plane of the curb they are in the crosswalk.
No one may suddenly leave a curb and dart into the path of a vehicle which is so close that it is difficult for the operator of the vehicle to yield. But motorists must watch ahead for pedestrians and be prepared to slow or stop to allow them to continue walking across the street.
Simply, a crosswalk is the extension of a sidewalk past the corner curb to the sidewalk on the other side of the street. "Pedestrian" means any person afoot or any person in a wheelchair or other mechanically propelled vehicle designed specifically for use by a physically disabled person.
Pedestrians who want to cross the street should look for cars and enter the crosswalk when it is safe to do so. This may mean stepping just off the curb or just leaning into the crosswalk a bit and putting out an arm to signal an intention to cross. While an assertive pedestrian may have the right to cross and expect a motorist to stop, it is one thing to be right, but you don't want to be dead right.