The driving experience you acquire in GT5 does somewhat help you with car control in real life,but to a cetain extent.
Real world driving is totally different to GT5 as there are so many variables we have to take into account like for example;
a) The reaction of "other" drivers on the road.
b) As some have mentioned,weather conditions.
c) Real world vehicles don't handle exactly as they do in-game.
Another example is with crashes.
Not sure if anyone has/have been in a vehicle collison,but I have and it ain't pretty.
Let me explain...
Many years ago...
I was driving my car(88' Toyota Celica ST162)
on a 2 laned road minding my own business when all of a sudden,a 6 tonne truck makes a right hand turn(just after a bus has passed on my right) from a T junction into my lane.The impact hits the right rear quarter of the Celica(exploding the rear hatch glass),spinning the car around to oncoming traffic in the opposite lane,hitting another car(shattering the passenger side glass) and finally coming to a stop on the curb.I was dazed and shaken but not hurt.
Funny thing was that the truck driver decided not to stop and kept going.
Luckily for me a good samaritan came to me with his number plates:tup:
And the car,a total write off.
Now,when one does have a collision with another vehicle in GT5..
The most you'll get is a spin or 2,and you're back on the track with barely a scratch on the vehicle.Yes,the GT series does not do crashes well(although NFS:Shift2 does quite a good job),but i'm merely comparing the differences.