Chausson APH521 (1953)
French bus Chausson APH521 (and its near-identical successor APH522),
which had a history of service both in France and post-war Poland. The latter were equipped with stronger suspension, as they were riding on bumpy roads of still rebuilding Warsaw (often overloaded with over 120 passengers!).
It had a pretty weak and faulty engine but it was otherwise pretty technologically advanced and ergonomic.
Available from 1953 to 1959. (Extended to 1960 for gameplay purposes)
Stats:
70 passengers
78km/h max speed
60 kW (80hp)
6.65 t mass
10.20m length
Polish license plates from PieoPlay