The instruction I've had on a race track (for cars) always taught brake first until the vehicle is under control, even if that means a complete stop. If you can't avoid an impact, at least you scrub off enough speed to make it hurt less......if the guy had braked to a stop, (without correcting)the worst that would have happened would have been a fall into the weeds/grass. It's hard to keep that kind of presence of mind when something happens that quickly, though.
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2020 Giant Defy 2
Fuji Cross Pro
Scattante 650-R trainer bike
'06 Kona Jake the Snake