Too much lag time when going from drive to reverse nd vice-versa? My F-150 could do better in that area but I also drive a Crown Vic that is awful slow to engage.
Find parking places that are "pull through" or back in for a quick getaway. ( I currently have a veh that doesn't like to go into reverse unless it has been driven > 20 miles, so know alot about this technique).
What year Vic? Have you checked the tranny fluid level recently? How many miles?