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Model X Crash on US-101 (Mountain View, CA)
- Thread starter mookhead
- Start date
You mean the canister that is part of the suspension system for the passenger side tire seen in this photo?
Model X Crash on US-101 (Mountain View, CA)
f-stop
Active Member
I'm curious about the comparison of effectiveness of those metal “smart cushion” crash barriers vs the plastic barrels of sand/water - aside from looking scary to hit, the metal attenuation barrier seems relatively complex to maintain and repair - and thus perhaps more likely to sit there a week or more waiting for reset/repair after an impact? ... agree it would be tragic if that barrier had been sitting there needing a reset before this accident...
It is only after you have missed all the signage that it looks like this:
They could add the white stripes in the non-lane for further visibility, as well as painting the big road numbers on the road surface, which they do down here quite a bit. Either way, I would bet it is still a barrier that gets taken out a lot if the 101 is regularly stopped and this lane is open from folks trying to skim the gap.
Here's the most interesting part about this image to me: At this point in the road with no gore treatment (such as cross-hatches or lane barriers/sticks), the space between the left HOV exit lane to CA-85 and the left HOV lane on US-101 looks like a full-width lane.
As humans, we know that (a) the solid-ish white lines, (b) the upcoming attenuation barrier, (c) the start of this area being a triangle (gore) where two lanes split and (d) (potentially) the variation in pavement composition means that this is not actually a lane, but image analysis of this still by a computer might classify that area as a lane, especially if it doesn't track the "history" of the lane starting as a gore, and if it's not trained to recognize the attenuation barrier ahead (because it's too small or because simply doesn't identify it as an obstacle).
At this point, any further speculation about what might have happened to cause the accident probably isn't productive, but if you normally drive this route with Autopilot engaged, it's possible to glance at the driver's console to see if a right-hand lane is detected here on the CA-85 HOV lane (or a left-hand lane on the US-101 HOV lane) before you reach the attenuation barrier.
Note that the Model X involved in the crash was a 100D model per photos in other posts, so it could only have AP2 (or AP2.5) hardware.
Apparently a lot of considerations are involved in deciding which type of "crash cushion" to use.
http://www.dot.ca.gov/hq/LocalPrograms/HSIP/2017/PocketGuide.pdf
https://safety.fhwa.dot.gov/roadway_dept/countermeasures/docs/CrashCushions_Nov2013Safelogo.pdf
https://www.azdot.gov/docs/default-...-library/crash-cusion-selection-procedure.pdf
https://mwrsf.unl.edu/researchhub/files/Report267/TRP-03-252-12 (revised).pdf
It looks like the sand-barrels get classified as "sacrificial" (non-reusable)
but the "smart cushion" sled device is classified as "Low-maintenance" which I gather to mean easy to reset/reuse. So I suspect a consideration is to use the metal sled device in areas where crash frequency is higher.
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Here is another old street view with it not reset (Jan 2017):
And Feb 2017:
And Apr 2017:
And Feb 2017:
And Apr 2017:
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As you move around the area the available photos change.
So many of them have it not ready to absorb an impact.
Partially collapsed (may be due to a slower speed impact or lighter car) Sep 2014:
Sep 2015:
Some of this may end up as discussion of CALTRANS budgets (or lack thereof) to reset these things in a timely way.
So many of them have it not ready to absorb an impact.
Partially collapsed (may be due to a slower speed impact or lighter car) Sep 2014:
Sep 2015:
Some of this may end up as discussion of CALTRANS budgets (or lack thereof) to reset these things in a timely way.
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If you go far enough back in time you find that originally they had a non-re-settable barrier.
Oh it looks like they did have barrels there in 2012 & 2013 before they switched to the sled...
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Man, that thing looks like it gets hit a LOT. At what point do you redesign the interchange? And, yes Caltrans shouldn’t be leaving it in the collapsed position for any length of time. If it takes a while to reset, they should be supplementing it with the barrels. Like the same day an accident takes it out, just bring the barrels by on a truck after the accident is cleared.
Agreed, or the standard response should be to come out with a barricade truck for safety, and repair it while the wreck is being cleaned up. Or leave the barricade truck in place until it is repaired.
You might consider sending that in to one of the local news stations covering the accident. They could then get a FoIA request to Caltrans for repair records and maybe find out if that barrier is regularly left un-repaired after accidents.
FlyF4
Son of a MX
Yes, AZ, but from reports, it looks more like exploding cells after the crash as well as what may have occurred during the crash. Those things can continue like popcorn.
Like the subject intersection, that one is also well marked; unlike the subject intersection, if it was an honest screw up you were in the correct lane already.
What that partucular intersection also had was a significant amount of pumpkin eating—people would ‘exit’ at old Middlefield but then jump right back onto 101 north and beat a half mile (or whatever) of traffic. I always suspected that was the reason for adding the bollards.
The subject intersection breeds similarly nefarious lane changing, but that’s clearly not what happened yesterday.
Possible. It seems like the fire was pretty slow to start after the accident based on the recent videos, so I was guessing the actual crash noise would be mostly impact and not major explosions, otherwise the car would have been engulfed before bystanders could even get the fellow out.
I used to drive this stretch daily and still do quite often. That barrier gets hit frequently so was likely already compressed. It also seems to be a hotspot for confused and bad behavior. I’ve seen cars come to a complete stop on the Y when they realized they were exiting on the wrong ramp and, especially when traffic is heavy, aggressive drivers speed up the lane they knew was wrong to pass a few more cars before diving back in to the lane they want. Sadly with a dead driver we may never know.
People have also questioned why AEB didn’t kick in. Cars need to be able to drive within 3m/10ft of such barriers at highway speeds and the system has been tuned to allow that so it probably can’t do much about a last second lane change in front of one.
Maybe the driver was being aggressive or maybe he he was the victim of someone cutting him off and forcing him into the barrier. It’s all speculation unless we hear from the drivers following or get some dash cam footage.
Separately, it irks me how some of the media coverage sensationally implies the driver died from the fire, which clearly happened after and in a pretty controlled manner.
People have also questioned why AEB didn’t kick in. Cars need to be able to drive within 3m/10ft of such barriers at highway speeds and the system has been tuned to allow that so it probably can’t do much about a last second lane change in front of one.
Maybe the driver was being aggressive or maybe he he was the victim of someone cutting him off and forcing him into the barrier. It’s all speculation unless we hear from the drivers following or get some dash cam footage.
Separately, it irks me how some of the media coverage sensationally implies the driver died from the fire, which clearly happened after and in a pretty controlled manner.
Like you and many others in this thread, I'm quite familiar with this piece of road, and like you, I've seen many people panic when they realize they're heading to 85 instead of staying on 101, and do all sorts of stupid things to get back to 101 at the last second.
I'm sure there's reasons it's designed like this, but in my opinion it's a bad design, and the fact that the crash barrier is hit so often should be an indicator that caltrans needs to do something about it. Until then, the crash barrier needs to be repaired/reset immediately after it gets hit, which from photos people have posted above, it clearly isn't.
Exactly, although the radar is quite capable of seeing the barrier, AEB systems are designed to filter out stationary objects to prevent false positives.
If you are going to crash, slow aggressively BUT DRIVE THE CAR. Pick your impact target. Many folk will freeze and hit what is right in front of them.
Taking a defensive driving course that has 'panic gates' helps. The absolute last thing you want to hit is a solid object in the front at 90°. Ram other cars, hit the k-rail on the side, roll the car up an embankment, spin, etc. Hitting a tree, large pole, large deer, bridge support, or interchange divider is often fatal at speeds as low as 45mph in new cars, and 35 in old cars.
There are literally thousands of these situations on California controlled access roads. As we get dumber, and cellphones and indash entertainment becomes more popular you are simply going have more folk kill themselves by not driving the car.
Think the 'thousands' is an exaggeration? Many off ramps have a situation that is potentially lethal at high speed. Nearly all transitions are this way. Bridges are this way. Some steel support poles. And most constructions. Thousands is probably just LA County alone.
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