Actually, I would go as far as to say Highway + University is NOT a helpful combination.
University is expensive and difficult to buy because of the potion cost. It ALREADY gains $5-cost cards, so the cost reduction given to you by Highway doesn't help you gain more Highways, so you're very likely going to be over-investing to get them, and neither card gives you the + buy so desperately needed when there's a cost-reducer in the kingdom. And University only gains actions, so you can't even use it to gain Provinces after playing three Highways!! (Could get a cheap Prince or Artisan or something, though.)
Highway/University is definitely not a thing. In a full-blown engine, with trashing, a good draw card, and a source of +buy, there is some possibility that you might play one or maybe two Universities in a megaturn engine featuring Highway, but the two cards don't interact in any meaningful way. If anything, they almost belong in the "annoying and potentially harmful" thread.
As a general rule, though, just make a mental note of [any cost reducer + any gainer] is usually a good thing. Not really an interesting card interaction; just how the game works.