;)
Get three or four bags of fast drying concrete (about $3 a bag) and make a permanent ramp there. Press some of the gravel into the wet cement before it drys to give it a blended in look. Most fast-drying concrete sets up in about a hour, so work fast.
You can mix it on a sheet of plywood with a shovel right there or do it in a wheel barrel or even in smaller batches in a 5-gallon bucket.
Do when you know it will have at least a few hours to cure until the idiot drives on it.
Are you serious?