Trucks are going to be harder to robodrive. There’s just way too much touch and feel in it (watch somebody back one up around a corner, the deliberate semi-jackknife is an amazing thing to behold). I think it’ll take an extra decade, so when robocars are standard, truck drivers got 10 years.
I think the real problem is more emotional. People are already scared of the big trucks. The majority of the population would be terrified driving alongside of driverless tractor trailers.
I’d like to see a robot drive a tanker on ice or a load of swinging beef in the mountains.