The probability here is that 50% of rooms will have traps, and only 1 in 3 traps will immediately trigger without warning, which I think is frequent enough to be dangerous but not frequent enough to slam a halt on exploration. I recommend attaching "Trigger" results to interactable objects whenever possible
If you feel that's too many, I'd use a d8, push "Trigger" to 8, "Danger Zone" to 7, "Signs" to 6, add a "Broken" column at 5, and leave the rest as nulls. That reduces the number of traps that are difficult to discover beforehand to 12.5%.
"Broken" implies a trap that's been activated and not reset, or that has broken down from age. Broken traps are a great way to telegraph that there are traps around, and create a sense of danger without actually requiring time to resolve in any detail.