Also, eastern Pennsylvania has the Appalachian mountains, and last time I checked, they were "real."
I'd agree that Californian snow-driving skills are a joke, and that Tahoe isn't actually that difficult compared to New England winters.
However, there really are terrain types that CA has (and Google tests its self-driving cars on) that just don't exist back east. There's nothing like CA 1 on the east coast, with windy 15mph switchbacks and a sheer several hundred foot drop into the ocean if you miss a curve. Nor do they regularly have to deal with the road being closed because of rockslides, or Tesla drivers who pass you illegally.
https://en.wikipedia.org/wiki/Tejon_Pass - 4,160 ft
Tejon Pass is on I-5 in northern LA County, and it is a huge trucking route. The grade is very steep between the Central Valley and the top of the pass, and is fairly challenging for trucks. There is no equivalent to those conditions in PA.
Also, if your impression of Tahoe is only the heavily touristed parts, your view is incomplete. The mountain roads in the Sierras have no equivalent east of the Mississippi.
Tejon Pass' major difficulty is the grade, and that's about it. PA may not have a highway that matches that grade, but many come close, and there are far more tight curves, typically far worse road conditions, and bad weather season is far more common than in N LA.
Highway trucking will be the first significant deployment of autonomous vehicles. One of the big challenges is Mountain West interstates.
I do agree that the NE US is a proper testbed for bad weather city driving, since no West Coast cities have really that bad winter weather, I'm just objecting to the claim that somehow Pittsburgh captures all the challenging road conditions that autonomous vehicles will encounter.
Personally I try my best to get as far off the beaten path as I can. Tahoe and surrounding areas is a cake walk compared to Pittsburgh.