A friend of my cousin's recently rewrote this, Hoy No Circula - Wikipedia, the free encyclopedia that discusses some of the intricacies of the new regulations.

As far as what you ask, if the vehicle is more than 8 years old, you can't get around the regulations. I think there are very few exemptions such as having a handicapped plate or diplomat, but in the case of the handicapped plate there is a place that I mentioned earlier where you would have to go downtown. We knew someone with a Texas handicapped plate and they were repeatedly stopped despite local handicapped plates being allowed a pass on hoy no circula. He had to get a special sticker for this.

If you have an 8 year old car at the moment, you have about 6 months or so left where you are able to get a cero sticker, after that though, you have to follow the regulations as mentioned in the wikipedia article, as your cero sticker won't be valid.

My cousin and several of his friends complained heavily to the American Embassy about this, but no help was forthcoming, and my cousin ended up leaving the country as a result, because he wasn't able to drive in the mornings to work, because his car was no longer eligible for the cero sticker.

I agree it could be a program to fund the new car dealers. However, the local D.F. mayor also wants Mexico City to be more like New York City, more public transportation and less cars, but in a city this size that won't work, because even the metro won't go up the side of the mountain to places like Edomex or even Santa Fe.