Final answer:
When a stop line is present at a stop sign, drivers must stop at the line.
Step-by-step explanation:
When a stop line is present at a stop sign, drivers must stop at the line. This means that drivers must come to a complete stop before the line, and only proceed when it is safe to do so. Stopping at a point that it is clear to see in all directions may not be sufficient, as drivers must follow the rules of the road and stop at the designated stop line.