Yes, American trucks can be quite scary on the Interstates. My experience is that they seem to drive above the speed limit and come up to your rear bumper. Also people drive far too close to each other, although it's the same in Europe. However trucks (and buses) here have a lower legal speed limit than cars on motorways and stick to it and may only use the inner two lanes (typically three lanes) so you can always pass them. There is the problem in the UK that many car drivers tend to stay in the middle or outer lane but not so in France. The French drive too close but do pull back into the inner lane quickly. The speed limit on French autoroutes is 130kph (80 mph) in dry weather, which I find quite comfortable. Regards.
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BillB