Anyone been to the Turkish Grand Prix ?

I am making plans to go to the Turkish Grand prix in August, the track looked so impressive last year I thought it was definitely worth a trip, plus I have been to Istanbul many years ago and know it is an interesting city. I am wondering about arrangements for getting from the hotel in the city out to the circuit. One article I saw said it is 18 miles away and the other said 90 km ? Anyone have any experience ? is it easy to get to ? and what about traffic ? any tips or advice would be much appreciated.