The formulas and online tables are not really accurate for real world modern cars. Example: https://youtu.be/0zbZweqlZPw?t=1m29s finds an empirical stopping distance of 11 meters at 40 mph. Actually closer to 8 mph than 18 mph!

Apologies, meant to type 18 meters. That's just for the braking - not including reaction time.

But the point is, she was well within the field of detection at that range.

Sure, what's the swerving distance?

The road was empty, I'd bet most drivers would steer away from a pedestrian on the road if only by sheer reflex.