Something does not add up in this article unless I am missing something. So safety features such as alert tone if engine kept on running for some time might be missed by older people who might have difficulty to hear but I assume that if a home has a garage to park the car then it should have and usually has a Carbon Monoxide alarm inside the house as well. Would not it start making loud alert noise when CO is increased at harmful levels?
Florida (where at least one of these deaths occurred) only recently began requiring CO detectors and only for new construction.
Requires that every building for which a building permit is issued for new construction on or after July 1, 2008, and having a fossil-fuel-burning heater or appliance, a fireplace, or an attached garage shall have an approved operational carbon monoxide alarm installed within 10 feet of each room used for sleeping purposes.
