Take piece of mat or light chain works better,fasten it onto the ramp with enough length to get to your rear tires.That way one set of wheels is running on the chain and keeping the ramp from kicking while the other is going up the ramp.Once your on,just wrap the chain up and throw it under the ramp so it's not in your way.I've seen people use a rubber mat under the ramp also,that will keep it from sliding,an old floor mat will work.My Alero is too low in front to start up the ramp,so I lay 2 short 2x6 boards in front of the ramp on each side,one about 3ft long,the other one about half as long,that way the tires hit one 2x6 then the next and actually hit the ramp about 3" higher than without them,I've never had a problem with them sliding once I'm on the ramp but that's front wheel drive so it pulls the ramp towards the car as your driving up it,that and the added height take some of the incline out of the ramp.I'm also working on asphalt.