Drive 235 ever morning from the mixmaster to downtown. Cruise set at 75, slow down to 65-70 for the cameras, speed back up to 75 around the "dangerous curve". They're a joke and everyone with a brain knows it. I've been driving this same stretch of road for the last 15 years and I've never seen one accident in this area. I do admit that I drive it during the early morning where there is little traffic and I'm usually one of the slowest drivers when there is bad weather.
On a side note, I think the DOT is going to do the right thing and force DM to get rid of these. Since everyone knows about them the only people you're penalizing are out of town drivers. "Welcome to Des Moines, here is your ticket, hope you enjoyed your time here".