It's not PR branding, cities actually spend time and energy and money actually making streets "worse" for cars. A common technique, for instance, is to alternate the side that cars are parked on. This creates a sinuous road where you're constantly doing little turns, instead of a straight-away.

This isn't just because of the width of the roads, because these didn't exist 30 years ago (in the states at least; they were starting to become common in the UK 30 years ago), but the houses haven't suddenly merged closer together.

I see in another reply you say these underperform. Citation? Fatalities are still lower in cities.