For cabs, driver overhead is about 49 cents a dollar while for truck its 38 cents a dollar [1]. However average transportation cost for retail goods is only 2-3% of total revenue [2]. So the net increase in revenue is actually about 1% for retailers - although its significant savings for trucking companies.

Now consider the fact that each truck carries 100s of thousands of dollars of goods. The wages you pay to driver can easily compensate for the insurance benefits because insurance companies may cover for human mistake but not for the algorithms mistake. Even if autonomous algorithm was 10X better than human, when it takes on responsibility of driving 1000 trucks, it would commit 100X more accidents than an average human. If a truck driver gets in to serious accident every 20 years, an algorithms will be blamed for a serious truck accident every 2.4 months - even if it was 100X better than human! It's an inescapable law of large numbers. (PS: this doesn't mean there are more accidents in total. It means number of blames assigned to same entity is much higher even though overall accident count is smaller).

The autonomous trucking had been attractive only for one reason really: You can avoid last mile. Highways are much more easier for autonomous driving where you rarely have to deal with crossing peds, traffic lights, round abouts etc.

[1] http://atri-online.org/wp-content/uploads/2017/10/ATRI-Opera...

[2] https://www.supplychainconsortium.com/Leadership-Forum/2009/...