I think you have a misunderstanding of my question. If i don't have cyclocomputer, how would I (myself, the rider) know to slow down if I don't know how fast I was going? For example, in a motor vehicle, you have a speedometer that tells you how fast you're going. So when a cop pulls you over for speeding, there's no excuse because you have a speedometer (or indicator) to let know you how fast you were traveling. For a cyclist who doesn't have s speedometer (cyclocomputer), there's no indicator to let you know your current speed.