Writing for Reason, Eric Boehm has a story showing that "all of the above" may be the right answer.
But I Am an Engineer
At first it seems like a story about government greed.
When Mats Järlström's wife got snagged by one of Oregon's red light cameras in 2013, he challenged the ticket by questioning the timing of the yellow lights at intersections where cameras had been installed. Since then, his research into red light cameras has earned him attention in local and national media – in 2014, he presented his evidence on an episode of "60 Minutes"…on how too-short yellow lights were making money for the state by putting the public's safety at risk."
But then it became a story about government thuggery.