(a) Except as provided in subsection (b) hereof, when two vehicles approach or enter an intersection from different streets or highways at approximately the same time, the driver of the vehicle on the left shall yield the right of way to the vehicle on the right unless otherwise directed by a traffic control device.
(b) At an intersection at which one or more streets or highways meet, but do not cross the others, the operator of a vehicle, traveling on the dead-end street or highway shall yield the right of way to any vehicle traveling on the street or highway which crosses the intersection, unless otherwise directed by a traffic control device.