Medford's new red-light cameras went live Thursday — although inattentive drivers have a 30-day grace period before police start issuing citations instead of warnings. After a new state law takes effect next month, the cameras may begin monitoring vehicle speeds as well.

We'll admit to a little hesitation about government-installed gadgets keeping an eye on us as we go about our presumably lawful business. Privacy is increasingly elusive in today's ever-more-wired society. Social media knows our likes and dislikes, and sells that information to advertisers who want to sell us their products. Banks and retail stores keep watch on us with video cameras.

But we'll accept the red-light and speed cameras for two reasons: They are stationary cameras focused on specific intersections, and they work.

Studies around the country have concluded that when red-light cameras are installed on intersections with high rates of red-light running and crashes, both tend to decrease. Medford's experience backs that up.

At the two intersections that have had red-light cameras continuously since 2005 — Biddle and McAndrews roads and Riverside Avenue and Barnett Road — crashes have decreased 45 percent. When cameras first went online in 2002 at Biddle and McAndrews, the number of reported red-light violations dropped from 25 per day to five per day within months.

The citywide number of citations for red-light running, however, is up. Police wrote 29 percent more tickets in 2016 than the previous year. If cameras at the two new intersections help get that number down, that will be a good thing.

The new cameras are monitoring Eighth Street and Riverside Avenue and Fourth Street and Central. Eighth and Riverside is among the top six intersections for accidents, with an average of 14 per year.

Critics who take a cynical view of red-light cameras will argue the program is just a way for the police department to generate traffic fines. But that logic doesn't hold up if the number of citations goes down because drivers are more careful. And reducing the number of crashes benefits everyone.