Solve the below given problem:
A truck driver driving at the speed of \(55\) \(km h^{-1}\) notices a road sign with a speed limit of \(40\) \(km h^{-1}\) for trucks. he slows down to \(30\) \(km h^{-1}\) in \(39\) \(s\). What was the distance travelled by him during this time? Assume the acceleration to be constant while slowing down.
The distance travelled by the truck driver \(=\) \(m\)
[Note: Enter the answer in two decimal values]