Police officers and others who work in law enforcement and public safety face special challenges: They have extensive contact with the public, including people who call 911 for health emergencies, and are some of the least able to stay isolated if they are at risk of infecting others. A major outbreak could test the ability of law enforcement to maintain public order in ways never seen before.

The contingency plans at many police departments include reallocating staff, deploying trainees and retirees and curtailing some service calls. To focus on critical needs, officials say they might have to respond to fewer minor car accidents, pull resource officers out of schools or delay responding to nonviolent crimes such as shoplifting and vandalism. The Miami-Dade Police Department said on Thursday that it would not enforce eviction notices for the time being.

“You will see all-hands-on-deck moments, where you are canceling vacations and taking detectives out of burglary and property crimes, for example, and putting them back on the street,” said Robert Davis, a former police chief in San Jose, Calif., who is now a senior vice president at a prominent security risk management consulting firm.

Even in normal times, many patrol officers typically have hundreds of “contacts” with the public every week — on calls, in hospitals, at traffic stops. They eat in crowded restaurants and use public bathrooms. They work alongside firefighters, paramedics and other medical personnel. And they often share police cruisers with officers who work different shifts, all of which make their vehicles into what some officers call “moving petri dishes.”