In Europe under hard braking by law either the hazard flashers or brake lights flash at a rapid pace, then keep the brake lights on steady and turn on the standard hazard flashers once the vehicle comes to a complete stop.
By EU standards, the emergency flashing lights under hard braking are activated when the braking force is greater than 6m/s2 for passenger vehicles. I came across an emergency braking situation on the interstate where a deer popped in front of the person in front of me. Their BMW activated the brake lights, but also turned on the rear fog lamp as an emergency braking light in a feature called Brake Force Display.
In the States, the two main brake lamps, not the CHMSL must stay lit steadily when braking no matter the force of the braking, however doesn't regulate whether or not the hazard flashers may turn on automatically and temporarily. Some states regulate hazard warning flashers while driving, but not while braking.
There has been a study where rapidly flashing brake or hazard lamps decreased a driver's reaction time in emergency braking situations: https://journals.sagepub.com/doi/ful...55/2014/792670
. Mazda does have this feature, however it is limited to markets outside the US: https://www.mazda.com/en/innovation/...ve_safety/ess/
Long story short, anybody able to program this into a CX-3 or maybe install a Raspberry Pi with some special coding?