The Amber Light With a Truck Behind You
You are driving a light truck at 60 km/h on a four-lane urban road, approaching a signalized intersection. The light turns amber when you are about 25 m from the stop line. Your truck is lightly loaded and the pavement is dry. In your mirror, a large commercial truck is following closely - roughly one car length back. The crosswalk is clear. A left-turning vehicle is waiting in the opposite direction. The amber phase at this intersection is short.
1. Do you stop or proceed? Reason it through.
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An amber light means stop unless you are too close to stop safely. At 60 km/h you cover about 16.7 m per second; from 25 m you need roughly 1.5 seconds of travel plus reaction time, and stopping distance on dry pavement is on the order of 35–45 m including reaction. That means a hard stop from 25 m is not comfortably achievable, and the close-following truck behind you makes a sudden hard brake dangerous. Proceeding through on amber is the safer choice here, provided the intersection is clear and you can clear it before the light turns red. Do not accelerate aggressively; maintain speed and go.
2. What if you had been 60 m back instead?
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At 60 m you have ample room to stop smoothly. The correct action is to brake steadily and stop at the line, signaling early and braking gradually so the following truck has time to react. A gradual stop from 60 m is far safer than a panic stop from 25 m. The rule of thumb: stop on amber if you can do so smoothly and safely; proceed only if stopping would be unsafe.
3. The following truck is tailgating. How does that shape your braking?
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It limits how hard you can brake without risking a rear-end collision. Brake early and progressively, using your brake lights as an early signal, and avoid sudden stops when you have a choice. But do not run a red light to appease a tailgater - if you cannot stop safely, proceed and clear the intersection. The tailgater's following distance is their responsibility, but your smooth, predictable braking reduces the risk to both of you.