A mechanics question

Today's question pertains to physics, and I can't figure this one out on my own through my empirical testing. So any engineers in the audience, please feel free to lend me your solutions!

The problem is this: The house I live in has a driveway that slopes downhill toward the street. The last part of the ramp kind of "curves" down to the rain gutter and flat street, and almost without fail, I scrape the underside of the front of my car on the sidewalk as I'm backing out. I've tried some workarounds, including backing out at an angle (is 45 degrees the magic number?), but each time I think I've got in figured out, I go into a slump again. But here's the kicker: I have no problem at all pulling into the driveway without scraping.

So here's the question: Is it possible that it's harder to go down the driveway without bottoming out than it is to go up? Or am I really that inferior of a driver in reverse, such that I succeed 100% of the time pulling in, and maybe 5% of the time pulling out? The angle never seems to be that magical on the way in. Furthermore, most drivers can commiserate with me -- there is an innate fear of bottoming out on your way down a slope to a flat plane, while you rarely feel it going up. I'm perplexed.