In NI ... and Ireland/UK in general, there is no law against "jay walking" per se, so it's normal to cross the road wherever you want. In practice, though, sanity tends to mitigate against just walking into traffic.
But one thing people do at home is weave among cars that have stopped at lights. It's why you don't drive fast alongside a row of stationary cars: somebody might just pop out and you'd hit them.
Here in California, though, *nobody* does that. Crossing the road among cars would be ... insane. People just don't do it. Not at all. Cross at the crossing.
Of course, there are specific laws against jay walking here, which probably counts. But also the roads are much wider, so you've so much further to go. But the big one is probably that nobody expects you to do it, so driving fastish alongside a row of stationary cars isn't so insane here, so folk kinda do it a bit, so you'd stand a non-trivial chance of getting creamed. Which would be bad.