Just wondering… is there any reason why trucks in the US have ‘noses’ and not a flat front end like in the UK/Europe?
So you don’t have to tilt the cab to repair the engine, when it inevitably breaks down. 
simple, they have much larger roads and room to turn not very good lock on them noses no good here
We have much more liberal length limits here and the standard maximum length of a trailer is 53ft and the difference between that and the overall length limit, which varies from place to place allows for a longer tractor unit with a hood and much larger sleeper than anything in Europe.
The reason is,The weight distibution of the axle’s is very serious here,all truck’s are built to the spesificacion of what they are to do in the field of work they are going to be used in,The road surface recovery is a lot to do with the dimention’s,i could go on but hey ho i don’t know all about it,take for instanse california,they have a 40ft rule to the axle,that’s because the off ramp’s etc are too tight for the 41ft bridge limit of most state’s.
Also the driver’s need somewhere to live,A cab over is not a nice accomodation for a driver.
While that all makes perfect sense, weight distribution has nothing to do with it, the axle weights are the same no matter where the cab sits on the chassis.
Bridge law doesn’t factor either, that is calculated from the kingpin to trailer axles, different lengths in different states and different points of measurement on the trailer axles, but nothing to do with the tractor unit at all.
The conventional took off when they removed overall length laws, in the US at least, Canada still has overall length laws and a maximum wheelbase of 244" so you don’t see many big sleepers there.
The two biggest factors in choosing a conventional over a cabover are ease of access to the engine for routine maintenance and driver access, believe it or not but claims to workers compensation for drivers falling out of their cabs was getting to be a huge cost to the industry, the average American is not a small chap and quite a lot of them had big problems climbing into a cavover, not hard to believe when you look at the step arrangement caused by the need (axle weights) to have the front axle mounted so far forward.
The other reason and probably the most likely is purely down to aesthetics, the long nose big bunk classic truck is a thing of beauty and that counts for a lot over here.