wow! if those kids did that here, in america, their a$$'s would be in jail so fast, they wouldn't be able to crap for a week!!
when i was a kid, we would skateboard down a freshly paved section of road that was only a 1/2 mile long, and not nearly as steep as that road. i would say the fastest we got going would have been about 20 mph, and it was never fast enough!! those guys rock!!