Or maybe people aren't slamming on the brakes during yellow lights any longer, but are instead clearing intersections normally - you know, they way they are supposed to on a yellow light.
Those “surprised Houston police administrators” are idiots. As both you suggest, and as it’s been well documented, while having red-light cameras decrease the number of broad-side accidents somewhat, the number of rear-end accident increases significantly. I wonder how much the “surprised Houston police administrators” get paid......
I was in Vienna a few summers ago and noticed that they have a countdown timer next to the yellow lights to let drivers know how much time they have before it turns red. No surprises. Perhaps we should do that here. Shorten the green light cycle by a few seconds, extend the yellow by a few seconds and count down from 6 or thereabouts. Maybe 1.5 seconds of yellow light for every 10 mph of the posted speed limit.