I have seen this at a few airports. The planes and service vehicles can share the same piece of asphalt, but planes always take higher priority and ground vehicles have to wait.
Game wise, the implementation can be by placing a road over an existing taxiway (or vice versa), OR by having a new object which serves as the “Intersection” and has the required code to handle both types of vehicles.
The advantage of this will be that the airport service roads will not get “boxed in” by having taxiways built across the airport.
Meaning, if there are taxiways going across the map, the service road need not have to go all the way around them (increasing distance and travel time). Instead, they can cut straight through.
This would become an important factor when the future development leads towards remote stands, emergency services, etc.
