Can anyone pitch in on a maximum cross slope of a driveway? I've got a street longitudinal grade of 10 percent over the frontage of a lot of 142' in length. The architect and client are hoping for two driveways that make a u-shape and then connect with the garage. As a result of that 10% grade on the street, I've been trying to get the two driveways to merge properly without a high amount of cross slope. Any recommendations?