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The Best Objective Study To Date on Truck Lust

Discussion in 'Model S: Driving Dynamics' started by tel, Feb 21, 2017.

  1. tel

    tel Member

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    I wanted to put to rest once and for all the notion of "truck lust;" that is, the feeling that the car will creep closer to a truck in an adjacent lane while autopilot is engaged.

    The experiment:
    I used my S85 with AP1 driving on freeways in Northern California. I had a friend tailing me, using a Blackvue 650GW dashcam to video my car and its position within the lane.

    To minimize bias due to lighting condition and shadows, I attempted (the best I could) to travel for several miles in one direction, and immediately travel in the opposite direction. I looked for trucks (actually, anything that registered as a "truck" on the display), using AP1, setting the speed to slowly overtake that truck. The speed was set so that on average, it took me about 7 seconds to pass the truck completely.

    I did my best to do this experiment at different times during the day.

    Because of the difficulty in finding trucks from time to time (not to mention my own time limitation and the limitation of my friend, who's tailing me), it took me almost 40 days to gather 22 encounters. The speed ranged from 25 mph up to 72 mph.

    We measured, using the dashcam video from the trailing vehicle, the relative position of my MS between the lanes before, during, and after passing the truck.

    Results:
    Sorry to disappoint many of you, but there was virtually no change in the position within the lane during any of the above encounters. In fact, the only time I was able to measure a position change is when the truck was offset in its own lane, nearing my vehicle. In that case, the MS moved AWAY from the truck slightly.

    I admit that this study was limited by the inaccuracies of trying measure my position in the lane based on dashcam video. I also concede that 22 encounters is not a huge number, and there's no doubt that I did not duplicate every possible driving condition.

    Conclusion:
    No measurable truck lust. My interpretation is that the reported truck lust is more likely an illusion, rather than a true vehicle movement.
     
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  2. Drone Flyer

    Drone Flyer Member

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    I agree wholeheartedly. Truck Lust is just an illusion thanks to the power of suggestion!
     
  3. malcolm

    malcolm Active Member

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    Please post the videos if possible. TIA.
     
  4. Max*

    Max* Not Banned

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    Sorry, that's not exactly how science works. Absence of evidence is not evidence of absence.



    It's a good observation, and thank you for doing a controlled experiment. But I can tell you this much, in the time since AP1, and over 35k miles on my car (probably 1/2 on AP), I've had truck lust happen twice. Both times I had to jerk pretty hard in order to avoid hitting the truck. I've probably passed 100s of trucks (thousands?) in that time period in over a dozen states. Could my "truck lust" really be something else? Sure it can. But neither of us has proven that it exists or doesn't exist.
     
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  5. tel

    tel Member

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    Malcom, there's LOTS of video, and all of it is just me driving next to trucks. I can get a few sample clips together and post links to them, if you're that interested in redoing the measurements.
     
  6. tel

    tel Member

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    Max, you're right about the science. And using statistical parlance, the null hypothesis is that "there is no truck lust." As you correctly point out, it's not possible to prove the null hypothesis (although we can have evidence to reject it, if the statistics are such). The best we can say is that "there is no evidence to suggest that truck lust exists." By no means does that prove that it's absent.
     
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  7. Max*

    Max* Not Banned

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  8. Max*

    Max* Not Banned

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    So we're in agreement, that's good. But 40 days with 22 encounters, in 1 state, maybe even in one small geographical location, does not seem statistically significant to me.

    Which is contrary to your title "the definitive word on truck lust" [emphasis mine, obviously]
     
  9. brucet999

    brucet999 Active Member

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    What you tested for is not "truck lust". Truck lust was an AP1 phenomenon that caused the car to sometimes swerve sharply toward the left rear corner of a truck trailer as the Tesla overtook it. There was nothing gradual or creeping about it, I know, because it happened to me 5 times in a single 1,000 mile trip in May of 2016.

    I don't know whether or not it has been corrected, but I am always extra attentive when overtaking a truck.
     
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  10. Max*

    Max* Not Banned

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    Why did you chose to do this? This implies you had about a 7mph differential with the truck.


    I wonder if speed plays into the experiment? What if the differential is 10mph? 20mph? Does truck lust become real then?
     
  11. tel

    tel Member

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    I saw those, Max. It's not clear to me how to interpret this video. Using the defrosting grill as a marker relative to the lane, it appears that the car initially moves away from the truck, then overcompensates back toward the right. Although "truck lust" is possible in this setting, so could it be an overcompensated lane correction.
     
  12. Max*

    Max* Not Banned

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    I believe it can happen both ways.
     
  13. tel

    tel Member

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    Max, the reason I chose this differential was entirely non-scientific. When I'm driving on the freeway and car sidles up to me matching my speed, I get a little annoyed. I didn't want the truck drivers to feel the same.
     
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  14. Max*

    Max* Not Banned

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    2nd video, he swerves left, then centers (already compensated), then waits, then swerves right into the truck.
     
  15. tel

    tel Member

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    Since clearly I did this test on the newest firmware (which I failed to mention in the opening post), I wonder if much of this issue has been corrected.
     
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  16. tel

    tel Member

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    Of course, I agree. How about I change the title to "The Best Objective Study To Date..."
     
  17. cgiGuy

    cgiGuy Active Member

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    I'll add my video to the list of evidence of its existence. If you watch the second time through (after the short black break) I've sped it up to help see the movement in spite of the wide angle lens making everything look rather mild. Also, the last clip shows the car move away from the truck, but departing the lane.. so I included that for fun.

    And I should add, that I started pulling these videos down from the camera after about 5-6 others. So it's just 4 of the MANY times that this happened on my road trip from TX to CA.

     
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  18. brucet999

    brucet999 Active Member

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    Respectfully, I will tell you that your characterization of "truck lust"as just an illusion is one made out of ignorance.

    Take it from one who has experienced 5 episodes in a 1,000 mile trip that my car suddenly swerving (not drifting) toward the left rear corner of truck trailers was no illusion.
     
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  19. habanero69

    habanero69 I Dont Need Cialis. I Drive an EV.

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    I have it and the video to prove. I'm too lazy to go back and find those vids, but trust me, your test PROVES NOTHING; well, maybe your car doesn't experience, BUT MINE DOES. :mad:
     
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  20. tel

    tel Member

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    #20 tel, Feb 21, 2017
    Last edited: Feb 21, 2017
    Lighten up. Or at least understand what statistics can and can not prove. I didn't say my test proves anything. In fact, as I mentioned in my brief statistical discourse with Max, it's impossible to prove any null hypothesis. My interpretation is my own. My results in this small, uncontrolled, limited study, confined to a few hundred square miles of testing range, are my results. Your mileage may vary.

    And of course, you have the chance to prove that it does exist. Do a similar test as mine under your driving conditions. I'm not talking about posting one or two videos that show this behavior. Use multiple passes by trucks, and do a two-tailed t-test (or, if you believe there's a better statistical test to use, then go for it) to compare mean distance from the highway divider lines before, during, and after a truck passing event. Report back the p-value. I'm totally open to a better study with more data under a wider variety of speeds and driving conditions.
     
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