"Darting" means moving rapidly from one place to another. If your eyes "dart," then your gaze is rapidly shifting from one point to the other.
I've never heard that expression used idiomatically, but if it is, it is obviously referring to paying too much attention to what's behind you (including past experiences) when you should be giving your full attention to what's in front of you. It doesn't seem to be an idiom. I think it's just a figure of speech to make the writing more dramatic -- the person's eyes are "darting," meaning they move rapidly back and forth from the road in front to the rear-view mirror of the car, or to the rear-view behind them.
It is caused when one has a epileptic attack , a serious case.
Black ice on road surface , cross-traffic running red lights, objects falling from other vehicles and into your path, animals or children darting into your lane of traffic.
Darting
Road to Joy - Bright Eyes song - was created in 2005.
vocabulary of the road
Free on Road!
run
Eyes Beauty (Gold of Eyes)
vocabulary of the road
Keep your eyes on the road. If their brights are on and you can't see, keep your eyes on the white line on the right side of the road to help guide you until they pass.