Lynnwood officials repeatedly have insisted that the city’s traffic cameras are a public safety tool. Any revenue, they say, is a byproduct.

As byproducts go, $4.7 million ain’t bad.

That’s how much revenue Lynnwood reported it has received because of red-light cameras and school-zone

cameras since January 2010. That figure represents only camera tickets that have been paid. Unpaid tickets aren’t counted by the city as revenue — and about one-fifth of all camera tickets issued have so far gone unpaid.

The Lynnwood City Council was flooded with complaints about the cameras last year. It changed its strategy for using cameras to enforce speeds near school zones. Now the cameras are watching only during times when safety concerns are most acute, like the hours when kids are being dropped off and picked up.

The city’s monthly revenue from traffic cameras has declined significantly since June, but the budget for 2011-12 still predicts that 11 percent of Lynnwood’s revenue will come from “fines and forfeitures.” Read: money that in large measure comes from traffic camera citations.

Lynnwood has issued 48,742 traffic camera tickets in the past 15 months. By contrast, police there wrote 17,081 traffic citations during the same period.Each camera ticket costs someone $124. A ticket issued by a police officer for a school-zone infraction starts at $189 for going a couple of miles over the speed limit, and the cost climbs depending on the speed. The amount is based on state law.

So far, Lynnwood’s biggest haul from traffic cameras came in March 2010: $527,685.29.

That’s $14.73 for every man, woman and child in Lynnwood.

In one month.