Women

From the article they cite at the top in an effort to claim that crash tests since the 1960's have only used male dummies.... ”GM also needed a test device to simulate a small female for testing of driver airbags. In 1987, GM transferred the Hybrid III technology to a dummy representing a 5th percentile female."

Not saying that a true representation of the female body isn't needed, just that this specific article is hyperbolic in its wording and is misconstruing it's sources to produce a desired narrative. Maybe best to find articles with a more nuanced, fact based reporting

There are crash test dummies of all genders and sizes

It honestly boggles my mind that in 2023 there are still no mandatory crash tests required for the female form.

Additionally, I drive a lot of hire cars and it’s shocking how many makes/models’ seatbelts would effectively garrotte me if I were to crash while driving.

People come in a lot of shapes and sizes. I kind of always assumed that crash test dummies would also come in a variety of sizes to test. I'm a bit shocked that we're just now getting to the "average adult woman" dummy model, considering I'm a statistical outlier in terms of size. But thinking about it now, that does explain a lot of the ergonomics of the cars I've driven.