Do all trucks have to seat belts?

In most countries, yes, all trucks manufactured after a certain date are required to have seat belts for all occupants in the cab. The specific date varies by country and the type of truck (e.g., heavy-duty vs. light-duty). However, older trucks may not have seat belts for all seats, or may have seat belts that don't meet current safety standards. It's also important to note that some specialized trucks may have different requirements.