Motor buses with air brakes and 3 or more axles may be ____________ or ____________.

The correct answer, which indicates that motor buses with air brakes and 3 or more axles may be 45' in length and 35' in length, is based on the regulations governing vehicle dimensions for safety and operational efficiency.

In Texas, as well as other jurisdictions, specific vehicles, including motor buses equipped with air brakes, have defined length limits to ensure they can safely navigate roads and intersections. Buses that are up to 45 feet in length can accommodate a greater number of passengers and cargo, while 35-foot buses offer a more compact option for areas where space is limited or where fewer passengers need to be transported. This flexibility allows operators to choose a bus size that best fits their operational requirements while staying compliant with state regulations.

The dimensions provided in the other options do not align with the legal standards set for motor buses with air brakes and multiple axles, which is why they are not the correct choices. Understanding these vehicle specifications is crucial for ensuring safety on the roads, proper vehicle operation, and compliance with local and state laws.