Concrete curb cuts: vertical or horizontal

I need to remove 30 feet of concrete curb next week so as to tie the current project's new driveway into the street. I met with the state highway fellow yesterday to go over the lane closing plan, and he sort of threw cold water on the cutting operation I had in mind. My concrete sub and I had planned to cut straight down (vertical) along the edge of the asphalt lane for the 30 foot distance, then (after cutting the curb crossways at both ends) use the excavator to pull the curb away from the street. But the state guy said he doesn't think we can cut it deep enough to do this. He says there is two inches of asphalt overlaying the lip (gutter) of the curb, and he doesn't know how thick the lip is. He is afraid that if we don't cut through completely that we will damage the asphalt lane when we pull back on the curb, and it's too cold to repair the asphalt.

So he wants us to try to cut the the top of the curb off horizontal to the top of the asphalt traffic lane. I don't even know if they make a saw that will lay on its side and make this cut.

Any advice for us? To make matters worse, we will have to do the project's second driveway in a couple of weeks in the same manner.

Concrete curb cuts: vertical or horizontal