Under the national standard Limits of Dimensions, Axle Load and Masses for Motor Vehicles (GB 1589-2016), what is the maximum standard vehicle height limit for passenger buses (excluding double-decker buses)?

1. 4.5 meters for all passenger coaches
2. 3.5 meters including rooftop air conditioning units
3. 5.0 meters on national expressways
4. 4.0 meters (double-decker passenger buses may reach up to 4.2 meters)