The Kevlar does work. But you need some method of keeping the heat and impact way from you
BUT what's is good is it helps keeping your insides inside. Less mess, less infection and less time in a&e if your skin is in one lump. It's easer to fix a broken bone then. Personally I have tested mx armour/Kevlar mix and it woke for lowish speed slides. For a heavy impact then maybe considering a Volvo or Alvis?
As noted above kevlar / aramid / etc does offer good abrasion resistance but, as with leather or other textiles, it doesn't offer impact resistance. For that you need a volvo. Generally armour will take the take the impact of landing, but then you need the abrasion resistance. Of course if you hit something big a solid, a 30 tonne truck for example, you will need something more appropriate. Like a mortician.
1x ambulance 2x rapid responce m/c paramedics 1x HEMS rapid responce car including a doctor and a gas man God knows how many plod 2x news crews And the London HEMS helicopter
Now thats a propa way to cause a traffic jam !
PS i was wearing leathers and the bloody armour in the legs span round allowing me to shatter my tib, fib and fracturing my feumer at the knee ball and breaking the pattella. Absolute waste of time wearing it. Hence i now strap the armour directly to me. So far so good during my test runs !