Should the driver make a run for it at an intersection with a yellow light?

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SUMMARY

The discussion centers on a driving scenario where a driver must decide whether to stop or accelerate through a yellow light. The driver is traveling at 50 km/h, 30 meters from the intersection, which is 12 meters wide, with a yellow light duration of 2 seconds. The car's maximum deceleration is -6 m/s², and it takes 7 seconds to accelerate from 50 km/h to 70 km/h. Calculating the necessary acceleration and distance covered in 2 seconds is crucial to determine the safest action.

PREREQUISITES
  • Understanding of kinematic equations for motion.
  • Knowledge of acceleration and deceleration concepts.
  • Familiarity with unit conversions (e.g., km/h to m/s).
  • Basic physics principles related to motion and forces.
NEXT STEPS
  • Calculate acceleration using the formula: acceleration = (final velocity - initial velocity) / time.
  • Research kinematic equations to determine distance covered during acceleration and deceleration.
  • Explore the implications of reaction time on stopping distance at traffic lights.
  • Examine real-world case studies of traffic light scenarios and driver decision-making.
USEFUL FOR

Drivers, traffic safety analysts, and students studying physics or automotive engineering will benefit from this discussion, particularly those interested in the dynamics of vehicle motion at traffic signals.

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Homework Statement


A person driving her car at 50km/h approaches an intersection just as the traffic light turns yellow. She knows that the yellow light lasts only 2s before turning red, and she is 30m away from the near side of the intersection. Should she try to stop, or should she make a run for it? The intersection is 12m wide, and her car's max. deceleration is -6m/s^2. Also her car takes 7s to accelerate from 50km/h to 70km/h. Ignore the length of the car and her reaction time.


Homework Equations


I don't know.


The Attempt at a Solution


I don't know. Please help.
 
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First, how much is the acceleration, when we say: if you hit the gas pedal in that car, you can accelerate from 50 to 70 km/h in 7 seconds?

You approach an intersection with a given initial velocity, and you have to cover a given distance, with a certain amount of acceleration. Will 2 seconds be enough time? Look for a formula that includes those variables.
 
Last edited:

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