You are right, Khalliwalli. There's no law saying you have to be at 100 if the limit is 100kph but there is a lane for slow moving vehicles also. In Salwa highway for example, some bus used to stay in 2nd lane and move at a rate of 60 to 70 kph. They must be some special kind of stupid I presume. I encounter this a lot because I am using that road twice a day.