The same risks identified in studies about ambulance responses apply generally to police and fire responses as well, though the dispatching criteria and cultures in those public safety disciplines can vary widely, experts said.

In the case of ambulances, some medical services strive to meet response times based on studies from the 1970s, when devices such as automatic defibrillators were not widely available in public settings. Some municipal contracts require private ambulance services to meet outdated response times, incentivizing the use of lights and sirens, experts said.

In rural areas, it would seem counterintuitive that ambulance and fire services would need to rely on lights and sirens to get through traffic, but they create an allure that can help in recruiting volunteers, Dr. Clawson said. “Running hot,” he said, is an adrenaline rush and makes the responses seem more exciting.

“It feels good and it feels like it works,” he said. “When it’s embedded in an institution — and a fire department is as good-ol’-boy an institution as you can get — it can be difficult to change.”

Wayne M. Zygowicz, now the facilities chief for South Metro Fire Rescue in Centennial, Colo., wrote in The Journal of Emergency Medical Services in 2016 that how easily an emergency vehicle is seen and heard depends on its color, size and markings, but that its lights and sirens are among the most important features.

“Our hearing is one of our most acute and primary senses,” he wrote. “Just try shouting loudly or blowing a whistle in a crowded venue, and you see how effective you are in getting people’s attention.”

Still, sirens have to compete with the improved insulation and sound systems of modern cars.

In an experiment conducted on a closed road by the former Monmouth Ocean Hospital Service Corporation in New Jersey, an ambulance starting 1,500 feet from an idling car had its siren set to “wail” mode. With the window open, the driver heard the siren, the experiment showed.