Does BusyCal support location based travel time alarms?

Yes, BusyCal supports location based travel time alarms.

For more info, see Locations, Maps & Travel Time.

NOTE: Location based travel time alarms are different from geo-fenced, location-based alarms. Geo-fenced alarms are only supported for iCloud Todos (not events). You create these by clicking on Alarms > Custom and then picking "Location" as the type of alert.