If you need a safety driver 100% of the time, the net gain in efficiency is 0%.
Edit: There's no comment in the article about there being period with no safety driver.
It did talk about "level 4 autonomy" based on a single drive with no disengagements (they mentioned they'd made a lot of drives but didn't mention their disengagement rate overall), doesn't sound like "achieving level 4" autonomy either-either.
If this trial period helps us improve the technology and eventually remove the safety driver after 1, 2, or 10yrs, that is a huge gain. What is the rush? -- every technology takes time to perfect. Lets judge the technology once it has had time to mature.
For owner-operators who live out of their vehicle anyway and are more concerned about getting work than sleeping in a hotel somewhere this could dramatically increase the volume of work they can take on (at least until fully autonomous trucks become widely available and humans are completely deprecated as truck drivers).
From that perspective it would be more efficient, not 90% but there would be significant gains.
But the trucks being that safe is the big question. The article describes a single trip without disengagement. Much more that is clearly needed.
So if I get woken up every 10 miles, am I really meeting the rest requirements?
Edit: Okay, remote driver access might solve this.
I mean, it's possible that demand for self-driving trucks means reliable wireless connections get implemented everywhere they can drive.
Also, Starlink is coming.
I80 goes SF to NJ, but no single interstate will take you from SF to NYC proper.
"I-80 does not enter New York City. [...] I-80's designated end (as per signage and New Jersey Department of Transportation documents) is four miles (6.4 km) short of New York City in Teaneck, before the Degraw Avenue overpass."