You get stroads when people put businesses on roads rather than on streets. When a road is "well-designed", that is, functioning as a route rather than a destination, it seems like a clever place to put a business, because people can get there quickly. But once you build a lot of commercial uses along a road, traffic gets worse because people are slowing down to enter parking lots, and it usually gets widened, making it more dangerous to cross: now you have a stroad. The "obvious" solution is not to allow development along roads, instead pushing this to streets (which may require building more streets), but the lure of tax revenue and short-term thinking is often too strong.