As a truck driver who has a little of this tech fitted to my truck already (adaptive cruise control and automatic emergency braking) I'm not worrying about losing my job any time soon. I live in a country which has lots of rain, fog and where it snows. The ACC and AEBS shit themselves and turn off when it rains heavy or as soon as the front of the truck gets a light covering of snow. Currently no autonomous car can drive in rain, fog or snow. The AEBS also has false positives ocassionally giving heart stopping collision warnings when I pass under certain bridges and more than once its slammed on the brakes when taking a gentle corner that has had metal posts put up along the kerb. Fortunately when it happened I wasn't carrying the load I was on the return journey otherwise there would've been a nasty accident.
And then there's the fact that with a truck there's a massive range of variables to consider compared to a car. A car never changes its dimensions, its weight is relatively constant. My truck changes length by over 40ft, its weight changes by up to 37 metric tonnes. Where the fifth wheel pin is, where the axles are, how many axles there are and whether the rear one is a steering axle on the semi-trailer all affect its cornering, manoeuvrability and reversing characteristics. All the loads on it have different effects on the handling characteristics and themselves need the vehicle driven to accommodate them. A tanker filled with 20 tonnes of milk for example requires a lot different driving technique to a flatbed carrying a 20 tonne slab of aluminium.
As I said, they can't yet even get the self driving cars to work anywhere where there's inclement weather which is why they're being tested in California so I'm not planning a change of job because of automated trucks any time soon.