Safer driving imperils municipal budget

Even by the time New Orleans started installing these, other cities were already taking theirs down due to diminishing returns.  So it comes as no surprise that...

The council was told that even though revenue from the city’s traffic cameras has fallen from $17.3 million in 2011 to $11.1 million this year, the number is expected to climb to $12 million next year as the city addresses a number of what officials called “technical challenges” with the cameras.

I wonder what the "technical challenges" were.  Yellows not short enough?