Got to explore the specifications of these monstrous Volvo B11R buses sometime back. They are real “civilized” monsters on the road.
It has an engine with 11K CC displacement. For a perspective, a Skoda Rapid gives you 1.6K CC. and a Honda City 1.5K CC. That’s amazing power for a 20K Kgs vehicle.
It has two 150 litres fuel tanks. That’s 300 litres of Diesel that it can (read Need to) carry. For a perspective, a Honda City would have a 40 litres tank capacity and a Skoda Rapid has a 55 litres fuel tank.
Talking about why it needs so much fuel on a journey, it guzzles a litre of Diesel every 1.39 Kms. and 11 litres of fuel always stays in it’s massive engine. Skoda Rapid’s mileage is considered one of the worst, among the sedans,  which is 10-16 Kms/litre of fuel. So, with a full tank, a Volvo B11R bus would need to refuel every 400 Kms. A Skoda Rapid can go approx. 800 Kms on a highway with a full tank.
The stats are ming-boggling. However, the genius of engineering provides you an unparalleled journey experience without making you think much about it. A bus that gives you the comfort of a sedan.
Impressive machinery!