You want to drive straight ahead. What should you do if the [red] truck immediately drives off on “green”?

When you see a red light and a truck is about to move off when the light turns green, the correct actions involve ensuring safety and clarity in the situation.

1. **Wait for the truck to move**: It's important to allow the truck to proceed, as it may have to navigate through the intersection or change lanes.

2. **Give a warning signal if necessary**: If you believe your vehicle's movement could confuse the truck driver or pose a risk, signaling can help communicate your intentions.

Following these steps is crucial according to German traffic regulations, which prioritize safety and the clear movement of all vehicles at intersections. This approach helps prevent accidents and ensures that larger vehicles, which may have blind spots, can operate safely.