OK I wasn't going to but here goes... Fisrt the speed isn't as important as the distance it takes you to stop...For instance:
I once crashed a stock car into a turn 4 wall at a mere 60 mph. Glancing blow, sprained the ankle I had on the brake pedal, ground to a halt, not so bad.
I also hit a tree with a 89 Camaro at about 40 mph. Sudden and brutal stop, misc cuts and bruises, very sore, not pretty but definetly worse than the 55 mph wreck.
I also lowsided my bike on track at TWS at about 75 mph. I hit nothing and bounced and skidded myself to a halt about 120 ft later with no physical harm. I was a little sore the next day but overall it was kinda fun.
Same track 6 months later I lowside (different corner) at about 75, skipped 30 ft and slammed into an airfence/tire wall/and my bike. This sudden stop resulted in a torn muscle along my femur, bent knee, two broken ribs, and a severly twisted ankle. Bad enough that I did not think it fun. Never the less I remounted later that same afternoon in order to protect my points in another class and...
Highsided at about 45. WTF you ask? I false neutralled and rode thru a corner without holding in the clutch. The tranny engaged the next lower gear and locked the rear tire sending over the hi-side and beating my head and back into the track HARD. This was no fun either...
The worse incident? I rolled an ATV at about 40 mph. Tangling with the ATV I managed to dislocate my neck and permanently twist my wrist. Oh I am sure I could have surgery but the wrist is still an issue nearly 6 years later. The neck injury healed well on its own but always gets out of sorts and I have to have a Chiro put it back right. No broken bones but the pain and recovery time has surpassed all the other injuries combined...
I could discuss my jet ski, Lawn mower, and bicycle accidents but hey you get the point....