A cousin of mine is planning a trip to Vermont, and he's going to start out in Bennington. He's going to use AAA to see how they route him, but I was absolutely amazed to see how Google Maps routed the trip.
My initial thought was I-64/I-79/I-68/I-70/I-81/I-88 to Albany.
Google said to go through Lexington, Cincy, and Columbus. Second choice was staying on I-78 at Harrisburg, then I-287 and the Thruway. Third choice was US 220/I-99 to I-80 to I-81 to I-84 to the Thruway.
What in particular is amazing about that routing? It's pretty straightforward, and if not for truck traffic, you could pretty much set cruise control all the way from Columbus to Albany.
You're going out of your way west to end up going east. A routing through Lexington or Cincinnati is not something I would logically consider for any destination to the east of me.
I'm pretty sure that Google has told me in the past to go through Lexington and Cincy to get to Erie, when my logical thought would be to go through Charleston on I-79.
If you're using Google Maps, it's very much operates as "at this time, do this". If it's not the most logical routing, there could be certain issues along what would appear to be the most logical route. If there's a crash causing a road to be closed, that issue going on now isn't going to be an issue when the trip is actually taken.
It also doesn't think ahead. If you're looking at an 8 hour route leaving at 4pm, it's probably going to detour you around certain cities and areas that are experiencing rush hour congestion. When you get to that area at, say, 9 or 10 PM, the quickest route probably won't be the same route Google Maps was telling you at 4pm.
That said, since the friend is in the planning stage, they can look at Google Maps at different times of the day to determine how traffic tends to be at those times. This is obviously going to be way more trouble than what most people will do when planning a trip, but it's better than looking at the route once and basing their travels on that "in the moment" review.