Safety requirements. Here's a crash test between a 2015 Nissan Tsuru, the least expensive sedan sold by Nissan in Mexico, and a 2016 Nissan Versa, the least expensive sedan sold by Nissan in the United States.
I've wondered if less safe vehicles (lighter, cheaper, smaller) could be made and required NOT to be on high speed roadways (above 45mph, freeways, etc.), or just have the US admit their regs are too strenuous.
When will this big government madness end. When will the US admit their regs are too strenuous so we can finally buy our cut rate industrial runoff baby formula in peace.
Your sarcasm would have made a valid point if modern sedans were the low bar in vehicular safety in the US.
Spoilers, The Versa is totalled, but the driver can probably survive. The Tsuru has the front half obliterated and the crash test dummy's skin comes out. No airbags on the Tsuru, but who cares, the car body can't survive the crash anyway.