Well looks like you've already been given some good advice. How long is a piece of string? I find I get to the outskirts of the CBD itself, within 20-25 minutes, then it can take almost that long again to actually get where you need to go and park. Given a good ride and easy traffic - 30 minutes all up. Given traffic, roadworks and every other conceivable obstruction to getting where we want to go - an hour or more. Buses, trains & trams are improving - good alternative if it works for you.