My two fastest rides home were because of situations like these. They weren't really bad emergencies I guess, but the kind where my wife says "Come home NOW." In one case, the ambulance had already come and gone and I just had to be home to watch the kids so my wife could go to the hospital and make sure everything was alright with our renter. If it were my own wife or child in the hospital, I don't know how much of a difference it would make how fast I got there, but there are plenty of options -- taxi comes to mind.