signatory @jfdecarolis.bsky.social also on bsky!

EPA's proposal: www.epa.gov/regulations-...
Our comment: www.cmu.edu/cit/veg/publ...
Brief summary: www.cmu.edu/cit/veg/publ...

w/ @paulijllo.bsky.social @costasamaras.com et al.

Still, if I were going to fast charge a lot, I'd prefer LFP.

LFP tends to be used on the lower-range EVs, which are the ones we need to fast charge more often (bonus!).

If I were buying a used EV, I'd also feel batter about an "iron-clad" LFP battery. It keeps going and going and going...

Automakers design battery management systems to protect against early death (e.g. by slowing charging or using less of the battery's capacity), so our standardized lab tests don't necessarily mean that fast charging your NCA/NMC EV will kill its battery.

LFP is cheaper and relies on fewer critical materials (www.nature.com/articles/s41...). Its main disadvantage is lower energy density (shorter range). But since LFP can take so much more abuse, more of its capacity can be used in practice, reducing or eliminating its key weakness

Replacing the battery every time it died would be prohibitively expensive in the extreme cases

Restricting the portion of the battery's capacity that the vehicle can use (as automakers do) can make NMC and NCA batteries last longer, at the cost of reduced range

When we used the entire battery capacity
- Fast charging killed NCA batteries (bottom, used in long range Teslas) rapidly.
- Heavy fast charging also killed NMC batteries (middle, used by most US automakers).
- LFP batteries (top, used in standard range Teslas) can take the abuse.

We cycled NMC, NCA and LFP batteries (the 3 types used in today's EVs) with varying amounts of slow charging (e.g. at home, level 2) and fast charging (e.g. highway rest stop, DCFC).

TNCs generally increase VMT relative to personal vehicle travel unless (1) more rides are pooled or (2) personal vehicle travel requires *very* extensive search for parking.

We don't have exactly that comparison in the study, but broadly TNC electrification addresses a smaller portion of externality costs than VMT reduction (because of congestion and collision costs).

“Superb” from Granger Morgan’s take

@destenie.bsky.social

@destenie.bsky.social

Made me want to vomit

Another example of work I presented at TRB recently that could be targeted now.

We found that ride-hailing technology mitigates effects of driver racial discrimination, but effects of residential segregation persist

www.pnas.org/doi/10.1073/...

Massive implications