In Netjets we have a fixed roster indeed. In the event of being assigned standby duty "at home", you'll have 45 minutes to leave your house from the time that you have been activated, another 60 minutes to arrive at your gateway airport terminal and another 60 minutes to the ETD of your airline: 2h45min.
If you have some friends/family near your gateway airport, you can possibly use that address. HR have been a bit picky on that in the past, but eased it in recent times. The bottom-line is: if you make your assigned airline, no questions will be asked. And nobody will get a verbal or written warning for missing an airline because of traffic on the road or a delayed train - as long as it does not happen every month.