Final answer:
A hand signal with the driver's hand and arm straight out indicates the intention to turn left.
Step-by-step explanation:
The meaning of a hand signal when a driver's hand and arm are straight out is a symbol that the driver is intending to turn left. Hand signals are used when the vehicle's turn signals are not functioning or as an additional way to communicate turning intentions to other drivers. The straight out hand signal, with the palm facing forward, indicates the intention to turn left.