The role of US regulators in the automotive industry is pretty different from what you seem to be expecting. They see their main goal is to set minimum, testable benchmarks for safety and give manufacturers freedom to achieve that in any reasonably justifiable way. The consequence of this is that almost nothing is required beyond meeting FMVSS and passing the tests it prescribes. ABS stopping distance is one of those tests, but a quick glance at the CR tests doesn't look like an FMVSS failure. The stopping distance simply wasn't up to industry norms.
Another consequence is that ISO-26262 and most other standards are completely, 100% norm-based in the US. They're used because the industry expects them, not because there's a legal requirement. You can deviate all you want and the only consequence is that regulators might take a closer look at your paperwork in the event of issues because they look unusual.
Another consequence is that ISO-26262 and most other standards are completely, 100% norm-based in the US. They're used because the industry expects them, not because there's a legal requirement. You can deviate all you want and the only consequence is that regulators might take a closer look at your paperwork in the event of issues because they look unusual.