The speed limits in Knock conform to those in the whole of County Mayo. Ireland uses the metric system, so the speed limits in the town are signposted inkm/h. You’ll need to drive at or under 50km/h (around 30mph) in the built-up and residential areas, and 80km/h (about 50mph) on the regional roads on the outskirts of the town. However, once again, in winter the speed at which you can drive will depend on the snowfall, so the actual speed that you can feasibly drive at can change, regardless of legal limits. Search rental cars on KAYAK