More often than not EU designs will put main roads apart from the activity centers, and have shared ways or slower ways inside dense areas. From a car POV it is subobtimal and ill thought out, while from people's point of view it's pretty great in general.
The most dangerous situation I can think of would still be where cars cross a bicycle road after doing a left or right turn in a crossing and not checking for trafic on the bicycle road.
We got all around Europe (Slovakia to Switzerland to Italy to Austria and back) all without a car. As a US citizen this priority can be frustrating at times because some cities even have no admittance for non-local cars, so you gotta park out of the city and transit in if you don’t have a local plate. But as a US citizen I am incredibly envious of the rail network and the downtown areas which are pedestrian only and entirely devoid of cars.
But also fundamentally we found that just as in states within the US, country to country things were vastly different with road quality. Many Eastern European countries are still weeding out corruption in their political systems and funds allocated for infrastructure are finally making it into public projects, so they often had worse roads and rail systems.
Modern metro areas or developed suburbs not so much.
When we drive in a different country we know that the driving rules are slightly different. We suspect that the conventions for driving are not quite the same. But the differences in rules and conventions of road design are mostly invisible. We may notice the most glaring differences like preferring roundabouts vs preferring crossings, but the large majority of those design principle differences, they are so close to invisible that we expect our expectations to still work. But they don't. Everything just feels subtly off, and sometimes there's a large difference standing out and we just declare that badly planned. Even when it's in fact perfectly in line with local expectationsand usage patterns, and works just fine (except for the confused foreigner). We notice a few standout differences and then blame every bit of traffic badness we encounter nonetheless on the few differences we consciously notice. The parts that work well are usually completely invisible, because traffic, in our perception, only exists when it's bad.
Rules/conventions on the design side exist for and can differ in just about every aspect, down to draining angle of road surface (do you drain symmetrically or to one side? Do you switch to draining to the inside in a curve? What about softer curves, sharper curves? A consistent threshold is very valuable, but if one country has a different consistent threshold than the other it feels "wrong" to everybody cross-driving even if no side is objectively better). Or the general shape of curves, some places have strict rules for keeping the second derivative of direction as flat as possible, with few, definitive jumps, others prefer a gentleness above all approach.