Here is some fascinating Boring Co efficiency analysis from X user Jon Twigge. I had been planning to write up something like this, but this post covers most of it plus some things I hadn't thought of.
The general theme is that the vehicles can be designed custom for the extremely specific and controlled environmental and operational use case of Loops. This specialization and operating model means that these "cars in tunnels" could have cost and energy efficiency that is conservatively at least 3x better than a Model Y being used on surface roads.
Youtube video with some more commentary:
Some things the post and video miss that I would add:
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- The total lack of humps and bumps in the roadway probably means the vehicles could have very low ground clearance and maybe side-skirt fairings like you see on some semi trucks (see example below). This would improve aero drag. Likewise, the rear wheel wells could have fairings (this one applies to surface robotaxis as well).
- The one- or two-seat vehicle models maybe could get away with only having three wheels and still be sufficiently stable.
- No rolling resistance penalty from rain, snow, or debris being on the pavement
- Generally mild temperatures underground means less energy must be expended on thermal control of the battery and cabin
