Probably already mentioned
1)Short trips-under 3 miles in the summer,a bit farther in the winter.It takes the Prius about 2.5-3 miles in 90 degree weather to get hot enough for it to go all electric and shut the ice down.We do lots of short trips.To its credit the Prius will still get 38-40 mph on a 2 mile trip with a cold(overnight) engine.The same trip, if extended to 4 miles will become a 50+mpg trip because I can get it to go all electric for 80% of the last mile.
Thanks,Charlie