Final answer:
A driver extending their hand and arm upward is using a hand-signal to indicate a right turn. This is one of several hand signals drivers may use to communicate their intentions to others on the road, which is crucial for safety.
Step-by-step explanation:
The meaning of a hand-signal when a driver's hand and arm are upward is to indicate an intention to turn right. In areas where drivers need to use hand signals due to a vehicle's turn signals being defective or non-existent, the standard signal for a right turn involves placing the arm out the window with the hand and forearm extended upward at a 90-degree angle to the body.
This signal contrasts with a left turn where the arm is extended straight out, and slowing or stopping is indicated by the arm extended downward. These hand signals are a form of communication with other drivers to indicate a change in direction and are important for safety on the road.