Seatbelts and Transporting Computers


I’ve just read an interesting post at Making Light about seat-belts [1].

In Australia seat-belt use is mandatory, you can be fined for failing to wear one – and the police (who help clean up the mess when someone dies on the road) are apparently quite aggressive about enforcement. Even aside from the legal requirement the use of seat-belts is fairly ingrained in Australian culture, people tend to use them even when they won’t get caught.

One of the things I like to do in my spare time is to take unused computer gear from IT companies (which they regard as rubbish) and give it to home users for recreational and educational use. Due to that and my work for some smaller IT companies I’ve helped many people load computer gear into their private cars and observed that most people will not take adequate care unless I coerce them.

A CRT monitor tends to be large and heavy, you wouldn’t want to get hit in the back of the head with one at 60Km/h. With some combinations of monitor and car you can fit a monitor in the front passenger foot-well, but usually the only place a monitor will fit is the back seat. The correct thing to do is to use the seat-belt to strap the monitor in place. It’s most likely that the monitor stand (the only part that allows a seat-belt to be attached) would snap off in the event of a serious crash – but this would at least slow the monitor down. Also don’t put the monitor directly behind your seat if you can avoid it, put it behind the passenger seat. In a collision monitor might be able to push through your seat and cause you a back injury.

Between 1992 and 2006 there were 78,000 acute computer-related injuries treated in US hospital emergency rooms [2]. The number of injuries caused by monitors peaked at 37% of the total in 2003 – this was largely due to monitors falling on people. Even without the speed of a car a monitor can be a dangerous projectile.

Hard drives have a lot of potential to cause damage, they are dense, hard, and the corners often aren’t rounded. Storing them above the back seat behind the driver’s head (as a friend once tried to do) is a really bad idea. Mythbusters showed that a box of tissues isn’t going to kill you in a crash, but a hard drive is much more dangerous. The typical car glove box can store a few drives. If you need to transport a box full then the front passenger foot well is a reasonable place. If your car rolls then that would suck, but it seems that people usually die when they roll their car anyway so just try not to do that.

A serious server (EG 2RU or bigger rack-mount) typically weighs 30Kg or more and is solidly constructed. The size and mass of such a machine makes it extremely difficult to safely store inside a car. The ideal place is the boot, but if that isn’t an option then behind the passenger seat is the next best option.

One final issue that I’ve been wondering about is the safest option for laptops that are in use in a moving car. A 3Kg Thinkpad would have to hurt if it hit you in the back of the head at 60Km/h. The child-seat attachments are solid anchor points that can be used for other things. I wonder if a laptop security cable could be attached to one of the child seat points. According to an exhibit at a science museum I can throw a tennis ball at 115Km/h, so I presume that laptop security cables are designed not to break when someone swings the laptop at that speed. Therefore if a car was driving at a legal speed in Australia before crashing then a laptop security cable should be able to stop the laptop. Preventing the cable from injuring the passenger on the way would be the difficult part.


9 thoughts on “Seatbelts and Transporting Computers”

  1. Paul Johnson says:

    You’re kidding yourself if you think the Kensington hole is reinforced to withstand a crash. You or I could easily walk off with a Kensington-lock secured laptop if we were to not care about case damage, as usually it’s not reinforced to the metal frame (if any).

  2. Anonymous says:

    Related to this, it really annoys me that many vehicles have a “feature” that puts the seatbelt into one-way retract-only ratchet mode if you pull it all the way out. This exists so you can lock a child seat into place, but it can also trigger just by leaning forward.

  3. Paul Johnson says:

    Sounds more like a bug, and a rather common one with worn out centrifugal clutches in GM seatbelts.

  4. Don Marti says:

    The back seat probably has LATCH points for a child seat. Attach the server’s handles to them with a strap or cable? There are also child seat strap attachment points on the package shelf or the back of the rear seat, but they’re only designed to be used in combination with LATCH.

  5. Anonymous says:

    @Paul, regarding comment 3: No, not a bug, an intentional feature, present since the day we owned the vehicle. (Not a GM vehicle, either.)

  6. Francis says:

    Most passenger car designs since the mid-60s will actually do quite a good job of protecting their occupants in a rollover situation (assuming you’re driving at legal speeds). In any case, objects in the passenger foot well could fly anywhere in sudden deceleration. A cardboard box isn’t necessarily going to keep the disks contained, either.

    In the case of CRT monitors, it’s probably the best idea, if you’re going to consider the worst case scenario of the stand snapping but still put it on the back seat, to place the monitor on the seat with the screen facing down, and secure around the whole monitor with the lap belt and over the stand with the sash (over the top of the stand). This will retrain the monitor quite a lot better. Even more so if it’s a manually tightened lap&sash belt.

    Overall though, if you’re going to be moving computer peripherals around, it’s best to use the boot. If you have cargo straps and/or nets, use them.

  7. etbe says:

    Paul: The Thinkpad T41p I’m using right now appears to have the lock hole as part of the metal frame. My recollection of the other Thinkpads I’ve used is that they appeared similarly designed. I’ve never tried testing this to destruction though. My EeePC 701 seems a lot less sturdy in this regard (thin sheet metal), but as the EeePC is significantly lighter the amount of energy that needs to be dissipated is a lot smaller.

    Don: Good point, I really should have thought of that!

    Francis: The cabin on a modern car should not be crushed in a rollover, but that is insufficient to protect the occupants. If you don’t have curtain airbags (or if the vehicle rolls a few times so the airbag goes down) then a head impact on the side window can cause death or brain damage. Also there’s lots of things that can go wrong when you get bounced around inside a steel box. As no government anywhere has a routine practice of testing vehicles for rollover safety we can expect manufacturers to keep doing little about it.

    I have found that due to seats being soft and angled it is often impossible to prevent a CRT monitor from falling over unless the screen (the center of gravity) is facing down.

    As for putting stuff in the boot, unless you have good boxes or cargo nets that is not a good environment to protect the computer gear. Any time you accelerate or brake hard or go around a corner things can slide around. The presence of tools etc in the boot makes things worse. I think we have to assume that any safety advice gets taken after the computers are protected from harm. I know this makes computers seem more important than people. :-#

  8. Paul Johnson says:

    I know about the Kensington hole trick because I find Kensington locks annoying enough that when I do spot them in use, I feel compelled to demonstrate their futility destructively.

  9. Toby says:

    There’s at least one well known case of an unsecured laptop becoming a deadly projectile in a car accident:

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