I'm a Chicagoan and I read all of the comments, so here's my response.
Parking violations at meters are issued "meter maids" armed only with a processing gun to take your information and print a ticket. There is significant profit in this, and you can be assured that your car will be ticketed if you have not paid the meter/it runs out of time. Since ex-Mayor Daley sold the meters a few years ago to a private company, I am unsure how much of the staff is private and public. I do know for sure that these tickets are paid to Chicago, so my guess is that it wasn't an outright sell but some sort of profit share. I could be wrong.
I think that mostly traffic beat cops are doing the towing and booting. I am unsure if this capability/equipment is available to any beat officer. I know for a fact there is CPD on these forums so maybe they'll chime in. From what I understand, they have some sort of "gun" that can read the license plate numbers from inside the squad car so it seems to be incredibly efficient. I've known many people to purchase the boot for three unpaid parking tickets. They are vigilant. BTW, it's a $700 fine as of two weeks ago to my knowledge. Big bummer, dude.
As far as the response time, I have personally dealt with this many times. CPD rarely have to respond to home invasions since most are done when it's obvious nobody is home. This has been done over the phone in Chicago for quite some time, that is, unless firearms were stolen (again, happened to me). They will attempt to file the report over the phone unless it is revealed that firearms were taken. SOP is for officers to arrive and take a report on the scene. This can take several hours. They will send at Evidence Technician (ET) several more hours later. They will advise you to call off work for this! If firearms weren't present, you have to request an ET to dust for prints (they will honestly tell you that this works less than 10% of the time). By this time, you're in it to win it and you will be lucky if your detective even calls you. You probably won't hear from them again because your case goes cold and sits on a desk. Cases have a 90% chance of going cold in Chicago (I saw this published in the Trib about five years ago).
I have not had an experience with a perp still on the scene (THANKFULLY). I have been told that emergency responses with perps on the scene are pretty favorable, but I also think it's dependent on location. Certain pockets of the city are known for high gang activity and while police presence is certainly there, I wouldn't necessarily count on them stopping any violent crime while it's happening. You will have good luck living near a precinct station. Mine is 3 blocks away and I have a police officer on my block, so although it doesn't grant me a shield, I feel better. Anyway, we all known violent crime doesn't work that way.
I'm sorry this has gotten long, but this reminds me of a girl who recently died here in Chicago who was the victim of a violent encounter with a criminal that broke into her home. This girl was very popular in the bar circuit and has many mutual friends of mine (I play in a band and subsequently know lots of people in the underground music community). The perp, shocked to find her in the home, pipewrenched her in the head and left her for dead. She died after about 6 months in a coma. No one was ever detained. This is how crime happens here. Cops respond after the fact. They have very little statistic closing rates in violent crimes and murders. They have great statistic rates in catching traffic violations.
My opinion on this "new" tactic is that it isn't quite new at all, it's just finally telling the public what most of us already know. Now that you're hearing it, maybe that we'll raise even more sentiment nationwide for carrying than, what I consider, a pointless murder statistic of homicides here in 2012. We are at a rate of about 2 per day already this year. Do you think we think our Chief or Mayor will let us use even one statistic in favor of concealed carry? Nobody here is under any illusion of the graciousness of our politicians. The point is, the CPD can't afford the response and the people know it. The wealthy already know this. Those expensive units are locked up like Fort Knox and everyone has ironclad insurance. Business as usual.
"Shut up, crime!"