Well, welcome to Bluff Park roads, stillfighting!  I've been going through the same experience for the past two years.
 
We live on a corner lot and have a stop sign on our property.  We, and our neighbors, also have small children.  The number of cars that actually "stop" at the sign is about 5-10%.  The number that "yield" at the sign is close to 60-70%.  The rest don't even slow down.  We contacted the police department.  They sent out an officer the following day who parked his motorcycle out of sight.  As cars ran the stop sign, he would go after them and give them a warning.  This went on for - better sit down for this - almost an hour before he left.  I called the police department back and they parked an old police car near the stop sign.  The compliance rate of stopping went up to 100%, even though nobody was inside the police car.  Imagine that!  
 
Alabama Code defines a "stop" at a stop sign as "ceasing movement", not "slow down, look both ways, then keep going".   So after the police department removed the old car (four days they left it, four days of nobody running the stop sign), everyone went back to their old ways.  I looked at alternatives, but could not find any (legal) ones.  So I contacted the city again and they did the same thing, placing a motor unit near the stop sign and giving verbal warnings.  One day, after almost getting hit by a teenage girl who was too busy talking on her cell phone to pay attention to the road, I blew a gasket with the police department.  They contacted the city engineer, who agreed to do a study on our road and the stop sign.  Their solution?  Turn the stop sign into a yield sign.  Needless to say, I found this to not be acceptable.  The other solution was to increase the size of the stop sign.
 
I now have a 48" stop sign on my property.  You can see it from 100 yards away.  It takes two poles to hold it up.  As people run it, they comment "Wow!  Did you see the size of the stop sign you just ran?  That's the biggest one I've ever seen, dude!".  
 
One day a child is going to be hit by one of these drivers who can't comprehend the meaning of "stop".  After that, I'm sure they will stop, but that won't be any consolation to the parent of the child.
 
So who's to blame for this?  The city?  No.  The police department?  Hardly.  The people to blame are the drivers who don't understand the meaning of "stop".  When I taught my oldest to drive I told her that I had two pet peeves about driving in residential areas and one pet peeve about driving in general.  The general pet peeve is that, regardless of where you are going, the seatbelt goes on.  That's for you, your passengers and it doesn't matter if you're the driver or the passenger.  The residential pet peeves are drive the speed limit and come to a complete stop at a stop sign.  I saw her coast through a stop sign - once.  Ask her if she'll ever do it again.  So back to the "who's to blame" thing, it is the people operating the motor vehicles.  Last year, when the police department increased their presence in Bluff Park by putting traffic enforcement units on Shades Crest Road, Park Avenue, Chapel Road and every other paved street in Bluff Park, residents complained because they were getting traffic tickets, mostly for speeding.  Well, don't complain if you're doing something illegal.  
 
The problem, according to the police, is that they can't cover all of Bluff Park at once.  According to the Bluff Park web site, we live in a "police beat" that goes from Sulphur Springs Road to I-65 to Hwy. 31.  That's one cop for a huge amount of space.  Sure, they have a backup unit, but it still leaves a bunch of space.  The opening of the sub-station helped a lot in keeping the patrol vehicle a little closer to Bluff Park at all times, but there are still the times when he or she are not here.
 
I suggest you keep calling and let them know that the problem is not fixed.  I also know of a place where you can purchase speed bumps for about $200, but the city seems to frown upon that.  I think if enough of us voice our displeasure about this to the right people, something might get done.  You may want to go as far as letting your favorite council member know.
 
One other thing, folks.  The speed limit on Park Avenue in front of the school is 15 mph in the morning and in the afternoon.  The flashing yellow lights are there to remind you, not to entertain you as you're zooming by.  If a car exits the school and you hit them going over 15 mph, it's your fault, not theirs.  Get my drift?  That extra 45 seconds that you have to spend driving through the school zone won't make you late for work, believe me.
 

Need more speed limit signs on shades crest. it would be nice to have one set speed instead of muliple speeds from 25-45 mph. The speed trap between tip top and mr p's is hot right now. I like it, but know its not fair. thats why I would like one speed limit on all of shades crest . I vote 25 mph from hwy 150 to hwy 280. its a neighborhood!

The best way to counter speeders is with more police enforcement.  There certainly is more now than we had prior to complaining to the city.  Problem is that the police I've seen hang out in the same places (Shades Crest, Park, Patton Chapel, etc.).  I think if they "spread their shot" a little, it would help slow everyone down