The Coach is a recurring vehicle, first appearing in Grand Theft Auto 1, and then, subsequently, in all of the GTA III Era games (including Manhunt), and is basically a charter bus.
The Manhunt, GTA Vice City, GTA San Andreas and GTA Vice City Stories renditions of the Coach are based on an MCI 96 A3 or 102 A3. These buses have a more boxy design, with colored stripes running along the sides.
In Manhunt, the Coach can be found in the level Born Again on the first street you come across. The bus is wrecked and abandoned.