Final answer:
Carriers operating a tractor outside of Alberta must have a Safety Fitness Certificate for vehicles exceeding 4,500 kg to ensure compliance with safety regulations.
Step-by-step explanation:
Carriers operating a tractor outside of Alberta are required to obtain a Safety Fitness Certificate if the vehicle weighs in excess of 4,500 kg. This is important to ensure that carriers meet safety regulations and have gone through the necessary checks and processes to operate safely on roads. This requirement is crucial for the operation of commercial vehicles that are used for the transportation of goods and passengers beyond provincial boundaries.