On my manual transmission car you can pretty reasonably guess your current speed based on the gear you’re in and on the engine sound, at least I can do that fro

On my manual transmission car you can pretty reasonably guess your current speed based on the gear you’re in and on the engine sound, at least I can do that from 0 to approximately 80-90 km/h (after which everything becomes too noisy, I need the speedometer). Failing that one can always follow the flow of traffic in order to remain on the safe side of the law.