it is a physical impossibility for a vehicle to roll uphill unaided, barring freak occurrences of nature, i.e. hurricane force winds, earthquakes, blah blah blah
the mass of a vehicle added to the force of gravity (mass of the planet) will always pull your car downhill, for a mass to pull your vehicle toward it, it would have to have a mass greater than the earth, and if it did the rest of the earth would also be attracted to it, meaning it would be at the centre of the earth, which is why at the centre of the earth is a great big ball of molten iron, being the most dense part of our planet.
for those of you who think it's magnetic, even though a magnetic force strong enough to pull a vehicle uphill would cause havoc with all different types of technology, take a compass there and find out where north is, if there is sufficient magnetic attraction north will point "UP" the hill (doesn't necessarily work if that way actually is north
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if you don't believe it actually is downhill, take a spirit level, not some pissy 300mm one like the guy in the video but a 1200mm or longer, if not do some GPS readings like some others have suggested, or get some surveyors equipment like a dumpy level and stick and measure the gradient, or at the very least take a glass and fill it with water and see how the water lines up with the top of the glass, take a plumb bob (preferably not made of metal so that there is no confusion with magnetism) and see how that hangs
there are many many things you can do so you can realise that your aren't actually going uphill