When you're only looking a few metres ahead, you significantly reduce your vision of the track in front of you.

vision 是名词，来自动词 see（看见），指"视力、视野"或"看的能力"。在这里指"对前方赛道的可见范围"。 track 的意思是"跑道、赛道"，指专门用于比赛或行驶的道路。