inattention to the road ahead; not watching where one is driving
Used especially in traffic contexts for failing to pay attention to what is ahead while driving or cycling.
The cause of the accident was inattention to the road ahead.
I rear-ended the car in front because I wasn't watching the road.
脇見運転 refers specifically to looking away from the road (e.g., at a phone or scenery), while 前方不注意 is broader and includes simply not paying attention to what is ahead.
Compound of 前方 (front, ahead) and 不注意 (carelessness, inattention).