From the Forum – Semi-Truck Blind Spots

by Prince Of Petworth December 12, 2013 at 2:15 pm 16 Comments

Semi-Truck Blind Spots:

“So an industrial design blog that I follow, core77, had an interesting post that I thought would serve as a good public service reminder for my fellow popville bikers. I had never really thought about how much the blind spot of a semi truck changes as the back of the truck articulates back and forth. As the truck turns, its mirrors don’t, leaving huge blind spots in places that they could see when they were going straight. The Core77 post shares a Youtube video that was made by Transport for London that illustrates just how big the truck’s blind spot is when it is starting to turn a corner. It was eye opening for me. Be alert and stay safe out there! Particularly as we get more and more big retailers and their big delivery trucks in the neighborhood. Don’t ever assume that they can see you on your bike.

(Keep in mind, that the video was made in the UK, so the driver and curb are mirrored to the opposite side of the truck here in the US.)”

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  • Anonymous

    “Don’t ever assume that they can see you on your bike.”

    thats key to all biking in the city.

    • Anonymous

      But also one that many bikers forget, as they try to ride up alongside and overtake slow traffic.

      • Anonymous

        it’s definitely okay to ride past and overtake slower traffic.
        just as it’s okay for traffic to overtake bike riders.

        • Anonymous

          I understand that. But if a car turns in front of you and doesn’t see you due to you being in the blind spot, you’re not going to have much – if any – recourse against the driver or his insurance.

          • Anonymous

            What do you mean?
            If a driver turns into you without checking his blind spot, or fails to get all the way to the right to make his turn (after checking blind post), he is at fault. Why wouldn’t the biker have recourse against the driver/his insurer?

          • Anonymous

            (Which is not to say you shouldn’t bike defensively. You should. Just addressing the point about lack of recourse.)

          • Anonymous

            @ 4:12 Anonymous

            You do realize that for trucks to turn on city streets they need to make wide turns? They can’t pull all the way over to the right, otherwise the trailer would never get around the corner.

          • Anonymous

            they need to use their indicator lights. that solves a lot of issues.

    • Sam Farmer


      As a biker whether you are right or wrong you will always lose an argument with a 2-plus ton piece of machinery.

      • Anonymous

        Don’t blame the victim. (Just wanted to go ahead and get that out the way…)

    • That Man A

      ride like everyone is out to kill you
      same applies to being on a motorcycle

      • Anonymous

        victim blamer!

      • monkeydaddy

        Alternately, view motor vehicles at intersections as though they were affectionate cats that want to rub up against your ankles. So cuddly! (HT: Bike Snob)

      • brookland_rez

        I second that. You have to be paranoid when you’re on two wheels. Also, I don’t advocate breaking the law, but if it comes down to breaking the law and having someone hit me, I would rather get a ticket than a funeral. I credit this line of thinking as a big part of why I’ve ridden 80,000+ miles without a single incident with another vehicle.

  • Anonymous

    I’ve never driven a semi, but two things strike me about that video. 1) the mirrors on the truck don’t look properly adjusted – half of the wide-angle mirror is focused on the side of the truck, which doesn’t seem useful. Swing it out to show less of the truck and you might see some of those riders. 2) The cab is angled, so this is what the driver sees *after* he’s started turning. Seems to me the time to check the mirrors is *before* you start turning – when the cab is straight, you’re going to see a lot more of the area beside the truck in the mirrors.
    Having said that, if I rode a bicycle, I would never assume that a truck this big has seen me.

    • monkeydaddy

      Second the notion that most people (including my wife) do not adjust their sideview mirrors correctly. Hint: lean to the driver’s side window, and adjust the driver’s side mirror until you can’t see the driver’s side of the car. Then lean toward the passenger’s side window, and adjust the passenger’s side mirror until you can’t see the passenger’s side of the car. Congratulations, now your rearview mirror, side mirror, and window collectively afford you almost 180 degrees of visibility.


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