

Ask HN: Is speeding up to pass the Yellow traffic light an "optimum" strategy?  - 31reasons

I think I am good driver just like any average driver but I always stop at the yellow light if I can. I in fact enjoy red lights because it helps me to relax , be in the now and get out of autopilot mode. But I see many people speed up at the yellow light to be on the "other side" and avoid the fate of waiting for a minute or more at the red light. Many times my friends complain that I don't speed up at the yellow lights.&#60;p&#62;So the question is, is it possible that speeding up yellow lights does not gain any time savings? that it is not the optimum strategy ? Its just our brain's impulse to prematurely optimize the task at hand ?
Can it be proved mathematically if its true or false?
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dmckeon

      Did you see the light turn yellow?
      How long does this light stay yellow?
      Is this the first of a sequence of timed lights?
      Is the intersection photo-enforced?
      Can you enter the intersection before the light turns red?
      Will speeding up get you into the intersection
      before the light turns red, or after?
      Do you carry comprehensive insurance?
      If a collision ensues, will you be at fault?
    

I doubt you will find a mathematical proof that is usable in actual traffic,
but a statistical approach might be usefully informative.

Have you measured the total possible minimum and maximum wait times for all
light combinations over some of your usual trips? (Hint: get your friends to
do the field work.) How do the "all red" and "all green" times compare
proportional to the total trip time? What are the chances that waiting for one
yellow light will increase the typical total trip time?

If none of that convinces you to wait for traffic lights, then take the MSF
(Motorcycle Safety Foundation) course, buy a small motorcycle, and report back
after a year of riding in traffic. The experience may give you a different
perspective.

~~~
31reasons
You probably didn't read my whole post. I don't speed up at yellow light like
most people do and I don't ever intend to. What I am interested in is a
theoretical insight into proving using graphs/probability theories with most
simplified assumptions. I don't intend to do the field work, it could be
better done with computer simulation but I am not sure if thats the better way
to approach the problem. This is a theoretical question only, no MSF
involvement necessary.

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lutusp
> So the question is, is it possible that speeding up yellow lights does not
> gain any time savings?

You're asking the wrong question. A better question would be, "is the risk of
a collision worth the time saved?"

There's an aspect of this scenario you're not considering. If you speed into
the intersection before the light turns red, you're legal, but other drivers
may not realize that the fact their light is now green doesn't mean it's safe
to proceed. Other aggressive drivers might jump into the intersection as soon
as their light is green and collide with you. It happens regularly, whenever
two aggressive drivers meet.

Driver A sees the yellow light and speeds up instead of stopping. He gets into
the intersection just as the light turns red. He's legal.

Driver B sees the green and jumps into the intersection, before noticing that
you're only halfway through. He's also legal.

Both drivers have acted legally, are "in the right", but both might be dead
right.

~~~
31reasons
I understand practical implications of all of that, but here I am interested
in proving that speeding at yellow lights is not optimal strategy even in
ideal (no traffic) situations in terms of reaching your destination faster.

~~~
lutusp
I don't think it is, considering you might not arrive at all. The possibility
of not getting there should be included in the list of outcomes. :)

