[bblost]

https://www.youtube.com/watch?v=bT3G-kcKN70

[Rehaan]

Saw this in the Accidents in India thread. Made me think of the importance of under-run protection instantly:



http://www.team-bhp.com/forum/street...ml#post3417124

cya
R

[Rehaan]

Construction:

Even a difference of a few inches in the construction can lead to a much weaker under-ride bar.

In this example the placement of the car, the car's speed, and the bar's length & material are all exactly the same in both tests. But, spot the difference in crash results:


(animated image)

Answer: The under-ride bar on the right has the vertical members much closer to the center of the truck. They should be further out to give the ends of the horizontal bar more strength.

Unfortunately this is a common problem with the construction of bars on Indian trucks.


Another downside:

In the US, the bars are only tested till 35 MPH (56 km/h). There's no guarantees above that speed...


Source

[mpksuhas]

Came across these pictures online, don't have the details. However, again shows importance of underun bars.

[QuickLink]

Originally Posted by mpksuhas

Came across these pictures online, don't have the details. However, again shows importance of underun bars.

Attachment 1722891

Attachment 1722892

Attachment 1722893

Just look at the way that Innova has crumpled. It's high time authorities should start checking under run protection bars on trucks strictly. No car is designed to take such a high impact on the A Pillar.

[ashis89]

Originally Posted by mpksuhas

Came across these pictures online, don't have the details. However, again shows importance of underun bars.

I am surprised to see the overhang the truck has. The rear overhang could accommodate the whole Innova (not at all happy to see this) and the Innova hasn't even reached the rear axle.

A smaller overhang could have minimized the damage in this case. I know that is not the ideal solution here but just a thought.

[Arwin07]

After understanding the importance of underrun bars in trucks and buses, is there anything a common man can do? Even a 5 star rated car occupants won't survive such crashes. So we can't do anything about buying safer cars in case of under run accidents.
1. What are the existing laws on mandating and enforcing underrun bars? Is it mandated in manufacturer level?
2. Depending on the current laws and enforcement, can we file a Public interest litigation to make 100% enforcement of underrun bars of scientific specifications?

[am1m]

Not just the under-run bar, but what speeds was the Innova doing to go completely into the truck like that?! This is scary. Just because the vehicle can do a certain speed doesn't mean the highways or other highway users are safe enough to do those speeds. Most of us need to think about that and ease off the pedal on highway runs.

[BenjiRoss]

We see so many of these trucks on the highway, that its scary. Recently I felt the magnitude of the rear overhang of a massive truck and the lack of underrun bars as I overtook two massive trucks - the first was unloaded and the second had a wide load. Both lacked under-run bars and it was scary.

https://youtu.be/wa4GvJxskco

[Rahul Rao]

Stricter implementation of rules will most probably get us under run bars, but what about position of under run bars, and the wedge shaped low front end bonnets that most of the small cars have.
Trucks and buses are allowed a rear overhang which is more than front overhang, not more than 3500mm from last axle, and not more than 60% of wheel base.
Rear, front and side under run bars in trucks and skirt panels in buses also have rules to fix their position, and the rules are designed with approach departure and cross over in mind.
For trucks and buses with wheel base below 5M the recommended clearance when laden to gross weight is supposed to be between 340 and 440mm, in the rear overhang this can rise after 2000 mm, and can go upto 600MM.
For trucks and buses with wheel base above 6M the recommended clearance when laden to gross weight is supposed to be between 340 and 440mm, in the rear overhang this can rise after 2400 mm, and can go upto 640 mm.
This clearance is barely adequate for our road conditions. Many times where we have big speed bumps, we see the road ahead of the bumps scratched by the front bumpers of buses when their rear axle is on the bump. Scratches from rear bumpers and under run bars also exist, but are less common.

Now coming to other vehicle design, the way the rear bumpers and under-run bars have limitations due to approach and departure angles, the smaller lighter cars have limitations towards higher bonnet due to aerodynamics, and many times the wedge shaped bonnet of a car squeezes it under the under run bar, this is quiet common where the forward weight transfer during heavy braking has lifted the rear part of the bus ahead of it, and the car has hit the bus at exactly that moment.

The under run bars should be fixed at 400mm, and vehicles with rear overhang beyond 2400mm should have fold able under run bars which our member Rehan has shown in post 11 of this thread. Cars should also be designed in such a way that the top of the bumper is of a height of minimum 500mm from the road surface. If need be the cars can have their headlights in the bumpers like the Harrier.

Rahul

[Sarvodaya]

A photo of Figo which went under the truck at high speeds. Happened in Mumbai.



A Video of the same.

https://www.youtube.com/watch?v=pKz9OrzWDHE

Another angle

https://www.youtube.com/watch?v=EVZbNo1BqyQ

[Rahul Rao]

What speed was the Figo driver doing. The truck is negotiating the junction at barely 10 kph, the biker slows down to let the truck pass. The car on the other side stops to let the truck pass, this guy enters from the junction at high speed with brake lights blazing, and goes under the truck from the side.
Rahul

[Rahul Rao]

Originally Posted by Rahul Rao

Rear, front and side under run bars in trucks and skirt panels in buses also have rules to fix their position, and the rules are designed with approach departure and cross over in mind.
For trucks and buses with wheel base below 5M the recommended clearance when laden to gross weight is supposed to be between 340 and 440mm, in the rear overhang this can rise after 2000 mm, and can go upto 600MM.
For trucks and buses with wheel base above 6M the recommended clearance when laden to gross weight is supposed to be between 340 and 440mm, in the rear overhang this can rise after 2400 mm, and can go upto 640 mm.
This clearance is barely adequate for our road conditions.

A video that show how the clearance and departure angle is barely adequate.

https://www.youtube.com/watch?v=rufd0sl_50s

Those in a hurry can start video at 38 seconds.


Rahul

[IndigoXLGrandDi]

Originally Posted by Rahul Rao

A video that show how the clearance and departure angle is barely adequate.
Those in a hurry can start video at 38 seconds.
Rahul

No offend intended but the Vehicle Registration Numbers are different in all the three cases.
Please Observe.


Here the rear of the bus is not shown while taking the Turn so cannot find out more about this bus. The focus of camera is mostly on the Front Side of Bus.



Here it is not Clear whether the bus is overloaded or the passengers on right side have gathered on the left side of bus. Probably the bus is overloaded.



Here the bend of the road is not steep and also the bus is seen to be legally loaded (no passengers seen standing- I have seen this video as well as posting this from mobile).

The Overhangs (Front and Rear) as well as Running Board touching the road (or ground) Cannot be Considered as A Reason for Non-Fitting of Under Run Bars. If any of these is/are touching the road, that vehicle should not be allowed to ply on the road. Simple.

[vigsom]

Although not an under-run bar, here is a pic of a bus sporting a flexi rubber skirt at the rear.

This would prevent stones and slush from the wheels being shot into the path of vehicles behind.