I’m planning a road trip, and went to Google Maps to find the best route. I was very surprised to find very different time estimates for one direction than the other. I dug through the data somewhat, and found some weird numbers.
From Allentown PA to Claysville PA, along I-76 westbound: Google Maps says this 299 miles will take 4 hrs 41 mins; that’s 64 mph. Bing Maps says 303 miles for 4 hrs 40 mins, at 65 mph. MapQuest says 302 miles in 5 hrs 13 mins, or 58 mph.
From Claysville PA to Allentown PA, along I-76 eastbound: Google Maps says this 301 miles will take 5 hrs 21 mins; that’s 56 mph. Bing Maps says 304 miles for 4 hrs 45 mins, at 64 mph. MapQuest says 303 miles in 5 hrs 18 mins; or 57 mph.
What the heck is the speed limit on I-76? The different sites seem to all have different calculations:
64 westbound, 56 eastbound, according to Google (faster westbound)
65 westbound, 64 eastbound, according to Bing (faster both ways)
58 westbound, 57 eastbound, according to MapQuest (slower both ways)
This might make sense if one site calculated by the legal limit, and another calculated by actual driving, but that would not explain Google’s calculation. Google might make some sense if there are actually different conditions in the directions (like two lanes eastbound and three lanes westbound) but would it really be like that for the whole 300 miles?
Can someone make some sense of this for me? Thanks!
I drive the turnpike once a month or so to visit my mom, and IIRC it’s 65 the whole way, except for the tunnels, which are 55.
It’s possible that the Google numbers are actual driving time, and eastbound had a lot of roadwork, which brings the limit down to 50 or lower in the work zones.
The speed limit isn’t the issue here. The turnpike speed limit lowers to 55 in the Pittsburgh area, but not until further west than the exit the OP would be taking.
What is at issue is that there is always construction in the mountain areas of Westmoreland and Somerset counties, which the OP would be driving through. That construction is ramping up right now and there is a five mile stretch near the Donegal interchange (IIRC) that’s one lane in both directions.
There’s also a segment of steep, winding hills between the Breezewood and Bedford interchanges where driving speed is reduced, and again right before the Allegheny Mountain tunnel outside of Somerset and again as you come down in the 3-4 miles before the Donegal interchange.
Further complicating things for the OP’s route is the segment on I-70 through Washington County and down to Claysville, where again, there is construction, and perhaps a lane closure, in the Belle Vernon area, or at least there was three weeks ago when I was last down there, and it looked like a long-range project.
Thank you Tumbledown. I think we’ll end up on I-80 to avoid the messes you’ve described. (We’re actually going from NYC to Columbus OH; the OP focuses on the part of the trip that was confusing me.)
But I still think something weird is going on. Everything you mentioned is in the western half of which I wrote in the OP, and what I wrote seems to be true for any section of I-76 in PA.
For example, let’s go from Allentown along I-76 and stop at I-70, just east of Everett. According to Google, that’s 167 miles, 2h50m, 59 mph, while the return trip eastbound is 161 miles, 2h31m, 64 mph. I can’t believe that the extra 6 miles is what slows the trip down by 19 minutes. I get similar results no matter which piece of I-76 I choose to look at.
The same piece, from Allentown to I-70 on Bing is 65 mph westbound, and 64 mph eastbound. And on MapQuest, it is 58 westbound and 57 eastbound. This is partly consistent with what I posted above: Bing is fast both ways, MapQuest is slow both ways, but while Google was faster westbound before, now they’re faster on the eastbound calculation.
The three of them must use very different calculations. And Google is doing something different for the two directions. Wish I knew what it was.
The correct answer is “it changes depending on the mood of the Turnpike Commission”. Seriously.
The PA Turnpike is converting to variable speed limits as they renovate sections. While I haven’t been on it in years, heading westbound from the Sideling Hill service plaza, the variable speed signs have been in place for a few years now. These signs light up to show different speed limits, allegedly depending on day / night and changing weather conditions.
The NJ Turnpike has had these for years - they’re so old that some of them are still done with neon-tube digits (like a neon sign, not a giant Nixie tube, though that would be cool).
