Final answer:
The 'S' condition code on a licence indicates that the driver is authorized to operate a school bus, having completed the requisite training and testing.
Step-by-step explanation:
Having the 'S' condition code on a Class 1, 2, or 4 licence signifies that the driver is a school bus operator. This code is used to identify drivers who are specifically licensed and authorized to operate a school bus. Essentially, it is a special endorsement that ensures the individual has met the requirements, including any necessary training and testing, to safely transport students.