Monday, May 22, 2006

You can run a red light

Does Speeding Make You Late?

Hypothesis – Does going faster than the speed limit make you late by causing you to hit more red lights?

This occurred to me a while back and I finally got a chance to test this out.

Ever notice when you are in your car and running late you seem to get stuck at every red light? I wanted to test if there was something to that theory…I chose the one variable that I thought I could test that being speed as the main cause of the constant stops at red lights. I mean what do you do when you are late? You speed!

My reasoning that it would cause you to get stopped at more red lights is this..

There are three kinds of traffic lights.

1.) Weighted – A weight is placed under the concrete that registers that a car is waiting and activates the change control system of the light. (These are becoming less common)

2.) Refractory – A laser is bounced back to a sensor in the light that measures the distance of the bounce and determines if a car is waiting

3.) Timed Light – Lights that change color based on intervals of time regardless of whether a car is waiting or not.

My theory is this when you are speeding you increase your chance of arriving at a light first…(If you are going faster than others you have a greater chance of arriving ahead of them…duh right). This increases the chance that you will have to wait at a light as no one is there to trigger the change control system ahead of you.

The test and the results

I plotted a course involving three streets(penn, lyndale, portland), two freeway off ramps(35w), three turn lanes,28 lights in total.

I drove the course 6 times. 2 times at the speed limit (35 mph, 55 on the free way)

2 times below the speed limit (25mph on residential and 45 on the freeway) btfw…driving slower than the speed limit is very stressful I have never been honked at or flipped off more in my entire life!!

2 times above the speed limit (45 mph on residential and 65 on the freeway)

And recorded the number of lights that I was stopped at and the time it took to complete the run.

(now this is not a perfect test as I was not able to control the speed the entire time...i.e. had to navigate through traffic etc., I also did not speed up to make lights ex. go faster than my set amounts and on all test runs I had a light or two that was questionable if ran it as it was changing from yellow to red.

Why did I do this? I was kicked out of my house for some showings and thought it would be fun to drive around and smoke and be a reject.

The results in a nutshell:

Speeding pays off.. On average I was stopped at three more lights when I was speeding but I arrived at the destination 6 minutes faster!!

Going below the speed limit was not only a horrific experience but also the worst offender when it came to hitting lights I was stopped at 7 more than the control subject and arrived 10 minutes later at the destination.
I made a cool graph of these findings in Excel if anyone would like to see them

So go for it! SPEED! Life is to short!!


Say Rah! said...

brian - i love this. i totally love this. i don't think you have any idea.

Rocketstar said...


This reminds me of you measuring the runoof angle on Portland Ave a while back.

Megsta said...

It's time you sold that house of yours so you can start participating in some normal activities.... hehehe! Always interesting Bri, to see how that brain of yours works!

dawnmarie said...

I was at the doctor today, and while I was avoiding eye contact with the woman examining my stomach, I was thinking of this.

did you do it at the exact same time of day each time? cause traffic patterns change depending on the time of day. and the light type (timed, etc) changes too depending on time.

Brian in Mpls said...

I did do it on almost the same time...granted the whole experiment lasted about 3 and a half hours so it was not super percise..

Todd and Amy said...

You are such a dork :)

Are you a Virgo, too?

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