Few deaths arouse more sympathy than the gradual, highly preventable deaths of a Passaic woman and her two young children last January as they tried to stay warm inside a parked car while its engine was still running.

Snow blocked the exhaust as Sashalynn Rosa’s husband shoveled snow around them. The 23-year-old mother, her 3-year-old daughter Saniyah, and her 1-year-old son Messiah were all killed when lethal carbon monoxide was thrown into the vehicle.

Within hours, thousands of dollars were donated to a funeral website, and Governor Christie signed legislation requiring the Motor Vehicle Commission to include carbon monoxide risks in its driver instruction and testing books as winter comes this week.

However, driving safety activists such as Janette Fennel have expressed mixed opinions about the concept.

“Anything that raises awareness of a lethal threat like this is a fantastic step,” said Fennel, the founder of the Philadelphia-based Kids & Cars road-safety nonprofit. “However, how can you teach someone to remember to turn off the car?”

Fennel understands the human weaknesses of ignorance and negligence that lead to carbon monoxide poisoning’s catastrophic vehicular toll better than others.

Clogged tailpipes have resulted in 30 deaths and 15 serious illnesses, accounting for roughly 80% of all deaths and illnesses since 2000, according to Kids & Cars.

Fennel’s group, on the other hand, is focusing on a much newer phenomenon: push-button keyless ignition, which has killed 20 people and caused 45 serious diseases since its introduction in 2003.

As a result of this technology, automobile keys have become essentially obsolete, as nearly all cars now have engines that start and shut off with the push of a button.

“Today’s engines run so quietly that it’s easy to forget that vehicles are still operating while parked,” Fennel noted.

Carbon monoxide gases are colorless, odorless, and tasteless, and they can enter other rooms in a house or apartment complex quietly. When breathed in, they replace oxygen in the body’s essential red blood cells.

The harm they do can result in chronic tissue damage, long-term debilitation, and death, as a New York couple learned in 2009, a North Carolina college professor in 2012, and a Florida grandmother last year discovered.

Carbon monoxide poisoning has been reported in New Jersey, with two people dying in a car in Hackensack last March. In February 2003, three men died in Paterson under similar circumstances in three distinct incidents. Tailpipes were implicated, although no keyless ignitions were involved in any of the incidents.

The Mayo Clinic in Baltimore offers several preventative measures.

Carbon monoxide detectors should be installed near all sleeping areas, and the batteries should be replaced twice a year.

Always open the garage door before starting the automobile and never leave it running.

Never use a gas stove or oven to heat your home, and never run a generator in the basement or garage.

Keep all fuel-burning equipment and engines well ventilated.

“A simple electronic switch should be able to shut down the engine,” River Vale resident Norman Wattman wrote.

“My Ford Fusion lets me know [the car is running] with two horn sounds and flashing lights,” said Brian Gunther, an Ocean County mechanic. “Why can’t other manufacturers fall into line?”

Although most modern automobiles include auditory devices that alert drivers when they forget to click the off-button, they fall short of the National Highway Traffic Safety Administration’s recommended level of 85 decibels.

As many readers have pointed out, many of the victims were elderly retirees with hearing impairments.

“It’s difficult to change a habit when you’ve been driving for 40 or 50 years,” Fennel observed. “However, even if a driver has good hearing, people of all ages can’t always hear the warnings above the noise of an automatic garage door shutting.”

Do drivers pay attention to their vehicles’ warning lights?

Ignition warning tones are so engrained in modern beeps, rings, and chirps in cars and phones that, as one Upper Saddle River reader put it, “we tend to ignore them.”

The NHTSA recommendation of 85 decibels, which is roughly the sound level of a blaring smoke alarm, would undoubtedly suffice. Nissan, on the other hand, deems 85 decibels to be “too high and may interfere with the driver responding to the alert.”

The National Highway Traffic Safety Administration declared keyless vehicles a “obvious safety threat” in December 2011, which could be remedied with a $500 million industry effort.

Carmakers, who are already facing airbag and brake lawsuits, have refused. The federal agency missed its own February deadline for enacting new keyless-ignition requirements.

What are our options?

It was suggested that the engine be turned off as soon as the driver exited the vehicle and pocketed the electronic controller or key. Regulators, though, appeared to be stopped by one question:

When do you think it will happen?

Is it true that lethal carbon monoxide may fill a house or apartment building in less than a half hour? Is an hour really an hour? Maybe ten minutes?

Whatever the answer is, the NHTSA’s decision is expected to affect only new vehicles, as current ignition systems, unlike recalled equipment, are not commonly recognized as damaged or defective.

In the meantime, class-action lawsuits are being filed in jurisdictions ranging from Florida to California.

One case filed in California seeks an injunction ordering eleven keyless car manufacturers to install automatic engine shut-offs, alleging 13 deaths.

Although there have been no fatalities as a result of keyless ignitions in New Jersey, carbon monoxide poisonings do happen.

Aside from the deaths in Passaic and Hackensack this year, a boy died in his Linden home in May, while two people were killed and 12 others were injured in December 2014 when carbon monoxide fumes overtook a Passaic building.

Similar vapors at a Garfield home took four people to the hospital on Christmas Day 2014. A week later, four workers at a Paterson dry-cleaning store were hospitalized after being overwhelmed by carbon monoxide.

In 2013, a senior-citizen complex in Pequannock was flooded with poisonous gas, forcing 150 people to flee.

Faulty equipment, such as heaters, ventilators, and generators, was blamed in these incidents. Doctors encourage individuals who are afflicted to seek fresh air and medical attention as soon as possible.

Dr. John LoCurto, head of emergency services at Hackensack University Medical Center, noted that just a small percentage of people visit emergency rooms.

“They’re generally dead before they arrive,” LoCurto explained.