Final answer:
To provide an adequate visual lead margin, one should scan and search around 12 to 15 seconds ahead of their vehicle. This offers enough time to notice and respond to unexpected issues or changes on the road.
Step-by-step explanation:
To maintain an adequate visual lead margin, it's recommended to scan and search 12 to 15 seconds ahead of your vehicle. That allows you plenty of time to identify and react to any obstacles or changes in the road condition. For instance, if you see a pedestrian crossing the road 15 seconds ahead, you'll have more than enough time to respond appropriately and safely.
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