Final answer:
Roadside assistance should be called when a car breaks down, as it provides support for mechanical failures and vehicular issues. It is not typically used for getting directions, when lost, or for taking breaks.
Step-by-step explanation:
The correct instance when a driver must call roadside assistance is when the car breaks down. Roadside assistance is a service designed to help drivers during vehicular breakdowns or mechanical failures. While getting lost or requiring directions may be challenging situations, they are not the typical circumstances for utilizing roadside assistance services. Similarly, wanting to take a break does not necessitate calling roadside assistance.
Roadside assistance programs, such as those offered by organizations like AAA, provide support for a range of issues including flat tires, dead batteries, or engine problems. It's important to understand that these services are available for actual vehicular issues, and usually, you need to be a member of such organizations to access their benefits. In emergent situations not related to vehicle functionality, such as a medical emergency, it would be more appropriate to call emergency services rather than roadside assistance.