One reason is that the total length of the truck and trailer is shorter. I think UK/European roads are more suited to that configuration

There's a max length, so a lot of Euro trucks have to keep the tractor unit as short as possible to avoid eating into their quota.

Trucks driving in small streets in centuries old cities need more manoeuvrability than trucks driving in newer cities build for cars. Different things are needed, you need more literal space for the engine to be able to be in front instead of below.

Europe has a limit on the total length of the truck+trailer. So a shorter cab allows for a longer trailer. The US has a limit on the length of the trailer, but not the cab, so the cab can be as long as you want. And a longer cab allows for better aerodynamics and more room inside, which is especially important for American long-haul trucks because most drivers live in the cab.

[removed]

European conditions and regulations favor a cabover configuration:

1. Shorter length. European countries have stricter overall length regulations.
2. Better overview when in dense traffic.
3. More urbanized and older road network also favors shorter and better overview as you have a better idea where the outer corners of your truck are (good when in tight spaces).

P.S: Meanwhile a conventional truck is more aerodynamic, it's easier to access the engine and it's a smoother ride since you're behind (and not over) the forward axle. So it's a favored configuration when you have longhaulers on long open roads (like much of the US).

US regulations limit the length of semitrailers, but not of combinations (a combination being a tractor and a semitrailer).

EU regulations limit the overall length of a combination.

Cab-over-engine trucks are more compact, but harder to service and less comfortable. Since US law doesn't require truck-trailer combos to be a certain maximum length, making the tractor more comfortable and easier to service is the natural outcome.

Another factor i don't see mentioned in comments here is maneuverability. Euro trucks have practically zero overhang in front of the front wheels, and a very short wheelbase, allowing much tighter turning.

A lot of (especially historic) cities in Europe are full of turns which would require US trucks to do multi-point turns to clear

More suited, yes, but also it's mandated by European law. That's the actual reason.

I didn't realise that. Although scania did a bull nose that I used to see quite often a few years ago

Also safety. COE in a Highway-speed accident is much more likely to cause major injury or death as opposed to a tug with more engine in the front to absorb the force of a collision.

There is a notice on the A1 to avoid Kimbolton village because of overhanging bodywork. Around Norfolk many villages are difficult with a long Cab on an Artic.

Just to add: this is not just the EU making rules for rule's sake

Remember europe is TONS older than the US. Plenty of twisty old roads and villages, far less straight, some really constrained routes.

Excessive length means trucks simply couldn't access some areas.