That explanation that psychologists came up with back in the 1950’s is incredibly specious because it’s not the same on the return trip because everything is backwards. The roads are different (and might require a different route due to one-way streets), and all of the sights are different because you are seeing everything from the other side. It is a completely different experience. Also, unless this is the first time you’ve been to that location, then the novel-there-familiar-back explanation makes no sense.
A better explanation is that the trip there is likely under a deadline while the return trip is more free. The pressure of trying to stick to a schedule puts added stress on the brain and makes time feel lengthened like most stressful or unpleasant situations have a tendency to do. The freedom of making it back at your own pace (melting ice-cream notwithstanding), relieves you of that burden and so the trip feels shorter.
I experience this ALL THE TIME. When I’m trying to get somewhere on time, it always feels like it’s INFINITELY FAR away. No matter how long I’ve been biking or driving, I’m still not even close. But when I’m not on a deadline to get somewhere, when I”m just casually going somewhere freely, time flies and everything seems close.
For example, I’ve biked to every corner of my city, and I’ve gone on 3-4 hour rides just for fun. I can reach downtown in what FEELS like no time at all, but when I’m rushing to try to get to the same area for trivia-night, I feel like I’m getting close, only to realize nope, I’m not even halfway yet, the point I think is “close” is still quite far away. (Actually, that could also contribute to the return-trip–effect, a false-anchoring-effect that provides an inaccurate sense of where in the trip you are.)