Which of the following is NOT an effective way to communicate while operating a forklift?

E-mail notifications are not effective for communication while operating a forklift because operating a forklift requires real-time, immediate communication between the operator and other personnel. When a forklift is in operation, it is essential for operators to receive instant feedback or instructions, which cannot be achieved through email due to its asynchronous nature. The other communication methods, including hand signals, verbal communication, and eye contact, enable quick and direct interaction that is crucial for maintaining safety and efficiency in a busy work environment. These methods allow for prompt responses to shifting situations, which is vital for preventing accidents and ensuring smooth operations around the forklift.