A safe speed allows you to stop safely in emergency situations. Unless otherwise posted, the maximum speed limit is 90 km/h in rural areas and 50 km/h in urban areas. Poor driving conditions will require you to drive more slowly. At no time should you exceed the posted maximum speed limit.
Driving safely can also mean not driving too slowly. You should not drive at such a slow speed that you hold back or block the normal and reasonable flow of traffic.