The 4 lane highway was a 55 zone, but the people of Boulogne posted a 45 zone, and cashed on. They won the lottery.
The speed trap was so effective, 60 %of the city income was from fines and forfeitures.
Of the 1008 arrests in 1961, 999 were for speeding. Accordingly 88% of the budget went to policing the zone, all 1.3 miles long and 2000 feet wide.
Greed was their downfall of course, so many complaints, etc caused the state road dept and a senator to get involved. They lost about 10 million dollars due to bad will, and people going out of the way to avoid the now nationally known, nasty little town that was a parasite on the highway and drivers just passing through. The few businesses and citizens left had their charter revoked 8 years after getting it, and 2 years after the senator took a side against them.
From a late 1960's Road and Track article by Richard Poe