Answer:
Four(4) seconds.
Explanation:
Under normal driving conditions, in a clear weather with good visibility and dry roads, a driver driving a normal sized vehicle is advised to stay at least two seconds behind the vehicle in front.
However for a 30 foot bus which is heavier than a normal sized vehicle, and takes longer to come to a stop when the brakes are applied, the driver is advised to stay at least four seconds behind the vehicle in front.