My concrete driveway slopes downward from the street to my house. Which leaves an 8" or more drop on each side of the drive in certain spots. That drop could easily cause damage to someones vehicle. Nighttime could cause someone real havoc, since there are no street lights. We were thinking of putting a layer of river rock on each side of the drive, but not sure if that would suffice this problem. We are trying to get it as level as possible to the drive, but not build it up with dirt and sod - just for it to be washed away. Are there any other suggestions?