How can we improve the safety of school/tour buses in the event of a collision?

[newhavendave]

With the increase of devastating accidents involving buses with head on collisions, I feel they need to be designed safer. I am on a mission to start a non-profit agency to design and manufacture composite exoskeleton's to retrofit buses. I don't know about you, but I would be scared to put my kids on a school bus after Google Image searching "school bus accident"! There is an extremely high quantity of momentum in a bus crash, and there are no crash protection features, this astonishes me and there is no reason for not updating bus design from how they were made 50+ years ago. See attached photos of some bus accidents this month.

I would like to design the composite structure to be impact, shear, and tear resistant. This is to spread the impact load over the entire front of the bus AND keep the roof from peeling back and allowing the obstruction to enter. My first design I propose using an epoxy resin to bond layers of Avistrap (very cheap, high tensile strength). I have over 2 miles of 1.25" 3600# b/s polyester strap. To prevent this fabric from shearing I will be considering sandwiching the strap fabric layer between sheetmetal (heavy and awkward). Then the molded structure will be affixed to the front of the bus with adhesive and self tapping screws. Unfortunately this design does not provide much impact resistance. I would like to keep the structure as thin as possible, less than 1 inch.

So if you get the picture of what I am trying to accomplish, please post suggestions for design, materials, etc, etc.. I am very open and willing for advice. Ask away!

-Dave
B.S. ME, Class of 2008, summa cum laude

 

[newhavendave]

Thanks folks. Yeah let's just forget about the American culture of pioneering ideas for the benefit of all and go back to whatever it is we stand for anymore (wars, tax cuts, fixing the cancers we created??), because I am pretty sure I am hearing a lot of talk about the 'what this country was built on', but very few people actually taking responsibility. Thanks, I guess I should not pursue the idea because I wanted to do it in my spare time with spare change but I would need a crew of engineers to help pilot the design. I can see I won't find that here. What is it? Do I need to prove myself for you to take me seriously, because of so many scammers and keyboard talkers on the internet today? Well I would like to do something about that to, and I would if I could. I would like to address our new culture much more than working on buses, this really is not my specialty, but somebody has to do it. Listen, if I can crash test one old bus with a swinging horizontal telephone pole from a gantry, it will 'go viral'. Help me out!

 

[Claws]

Yes - prove yourself. Come up with a design idea, and people will take it from there.

 

[AlephZero]

I think you are trying to solve the wrong problem. A 1985 study of US and UK accident data showed

93% of accidents were caused wholly or partly driver error or other human factors (e.g. alcohol).
In 57% the only cause was human factors.
12% were caused wholly or partly by vehicle factors.
In 2% the only cause was the vehicle.
(source: http://en.wikipedia.org/wiki/Traffic_collision)

Compare road safety in the USA and the UK. The vehicles are about the same standard (at least when new). The USA has about 3 times as many deaths from road accidents per year per million of population than the UK, even though only about 4 states in the US have an average population density greater than the average for the whole of the UK.

I suggest you find the real cause of those differences, and work to fix that. Exoskeletons for school buses is just a sideshow.

 

[xxChrisxx]

A thin 'exoskeleton' won't do much to solving the problem of crash safety. IT just doesn't address the fundamental problem. I assume this is to retrofit rather than redesign.
To improve crash safety you need crash structure, ie crumple zones. You want the outer structure to crumple and deform as much as possible leaving a 'safety cell' intact.

As stupid as it would look, your best bet would be to stick an equivilant of SAFER barriers on the outside of a bus. You could use a collapsable foam sandwitched between two composite layers. It increases the impact time (reducing forces) and allows dissipation. Replace any bench seats with proper seats and add seatbelts that must be worn.


Also I would guess that frontal impacts are unlikely to be a problem for the children. They may be injured but the liklihood of a fatal accident would be low as they are far from the point of impact. I would have thought that side impacts were of far greater importance.

 

[Unrest]

There are lot of conflicting effects in something like this -

Put an extended crumple zone on the front and it'll wipe out pedestrians while turning, as well as looking stupid :P )

Make the roof stronger and it'll be more likely to roll over, as well as generating more greenhouse gasses (think of your childrens' children!).

Make the outside stronger (effectively disabling the existing crumple zones) and it'll increase the force of impact for passengers as well as other vehicles.

Do anything and it'll cost money.

Spend money on busses and you're potentially taking it away from something that might save more lives, like breathalizers for bus drivers!

It needs a higher level investigation before working on the nuts and bolts to avoid doing more harm than good.

But good on your for putting road safety ahead of some of the more trivial 'dangers' people usually worry about. This is a serious issue, perhaps not so much for buses as cars and motorbikes.

Aleph you may have mentioned the cause of safer UK roads yourself. High population density allows them to have median barriers all the way from London to Glasgow! Unbelievable!

 

[AlephZero]

Aleph you may have mentioned the cause of safer UK roads yourself. High population density allows them to have median barriers all the way from London to Glasgow! Unbelievable!

There are no barriers at all on most roads in the UK, not even on many of the main routes.

I have no idea why the US and UK accident rates are so different, but the evidence strongly suggests that the main cause of accidents is not vehicle design.

One obvious difference: in the UK, if a bus has seat belts fitted, it is illegal for passengers over age 14 not to use them or, to stand. (There is a campaign to reduce that age limit, but there are issues about children using seat belts designed for adults). But note, it is not compulsory for buses to have seat belts in the UK and many buses used only on urban routes with 30 or 40 mph speed limits do not.

A google search suggests only 6 states in the US have any legislation on bus seat belts...

 

[newhavendave]

I think you are trying to solve the wrong problem. A 1985 study of US and UK accident data showed

93% of accidents were caused wholly or partly driver error or other human factors (e.g. alcohol).
In 57% the only cause was human factors.
12% were caused wholly or partly by vehicle factors.
In 2% the only cause was the vehicle.
(source: http://en.wikipedia.org/wiki/Traffic_collision)

Compare road safety in the USA and the UK. The vehicles are about the same standard (at least when new). The USA has about 3 times as many deaths from road accidents per year per million of population than the UK, even though only about 4 states in the US have an average population density greater than the average for the whole of the UK.

I suggest you find the real cause of those differences, and work to fix that. Exoskeletons for school buses is just a sideshow.

All-

First, I can appreciate your desire to work on the bigger issues. But know, that other people are working on those now, and God speed to them! I agree, something must be done to prevent drivers from acting this way, or it will only get worse, by the perception of driving a bus that could double as a battering ram. PM me if you would like to talk more about this as a side gig. Or assert your desire that these would be BAD so that I can review my idea from another angle.

The Bronx bus accident would have fallen in the 93%. But we can agree that the majority of the deaths from the back of the bus on forwards were due to the pole. The statistical collection methodologies of this stat are now in question. The pole ripping through that bus like some teenagers with a bat through a row of mailboxes. He wouldn't get very far with a sheet of plywood in front of the first box.

Just looking for the science people. Remember when you used to hear, "you may be on to something, boy!" Well, feed 'this boy' some fodder and let him run with the idea! Keep an optimistic mind and you will let many great ideas froth to the top.

Specifically low cost recycled material ideas.

Thanks All - Dave

 

[newhavendave]

There are lot of conflicting effects in something like this -

Put an extended crumple zone on the front and it'll wipe out pedestrians while turning, as well as looking stupid :P )

Make the roof stronger and it'll be more likely to roll over, as well as generating more greenhouse gasses (think of your childrens' children!).

Make the outside stronger (effectively disabling the existing crumple zones) and it'll increase the force of impact for passengers as well as other vehicles.

Do anything and it'll cost money.

Spend money on busses and you're potentially taking it away from something that might save more lives, like breathalizers for bus drivers!

It needs a higher level investigation before working on the nuts and bolts to avoid doing more harm than good.

But good on your for putting road safety ahead of some of the more trivial 'dangers' people usually worry about. This is a serious issue, perhaps not so much for buses as cars and motorbikes.

Aleph you may have mentioned the cause of safer UK roads yourself. High population density allows them to have median barriers all the way from London to Glasgow! Unbelievable!

Perfect! Thank you! I will think about this and get back on here. But also, I ask you keep in your mind the image of a thick rubber mat covering the vehicle, but also a mat that is rip, cut proof, tear proof proof and not stretchy.

-Dave

 

[newhavendave]

A thin 'exoskeleton' won't do much to solving the problem of crash safety. IT just doesn't address the fundamental problem. I assume this is to retrofit rather than redesign.
To improve crash safety you need crash structure, ie crumple zones. You want the outer structure to crumple and deform as much as possible leaving a 'safety cell' intact.

As stupid as it would look, your best bet would be to stick an equivilant of SAFER barriers on the outside of a bus. You could use a collapsable foam sandwitched between two composite layers. It increases the impact time (reducing forces) and allows dissipation. Replace any bench seats with proper seats and add seatbelts that must be worn.


Also I would guess that frontal impacts are unlikely to be a problem for the children. They may be injured but the liklihood of a fatal accident would be low as they are far from the point of impact. I would have thought that side impacts were of far greater importance.

Interesting thoughts. Side impacts tend to be lower in height than the child sitting so the force is not in line with the child. Plus most things that hit buses on the side are of less momentum which essentially doesn't move the bus into the car.

We don't need a crumple zone, that is to save the driver. The crumple zone is already built into the head of the bus around the driver, the expendable pilot risking life. The tall seats prevent people from being launched forward in a head-on. Most bus accidents I believe now, have few passenger injuries beyond the first rows. It would not take much up front, to compliment the steel, to make that number zero passengers.

I disagree with young kids having to wear seat belts as a solution. Moving around freely when the bus has stopped increases valuable child interaction environment. Kids need to have respect for the bus driver and stay seated when moving.

Thanks for the thoughts, I appreciate it! And I hope I helped you understand my points. Dave

 

[xxChrisxx]

We don't need a crumple zone, that is to save the driver.

It's to prevent injury to everyone inside by reducing imact forces from being transferred to the occupants. Which basically means the little kiddies won't be thrown around the bus in an accident.

The crumple zone is already built into the head of the bus around the driver, the expendable pilot risking life.

That is tremendously callous. It's that attidude is the reason for more fatal acidents on US roads. Why not just make the bus more safe for all occupants? Those who are seen as expendable will have death accepted more readily.

I disagree with young kids having to wear seat belts as a solution. Moving around freely when the bus has stopped increases valuable child interaction environment. Kids need to have respect for the bus driver and stay seated when moving.

I thought the premise was crash safety? Obeying the driver won't do you much good when you get thrown from your seat. A seatbelt can be easily unclipped when a bus is stationary. They are by far the single biggest contributor to saving lives in a collision.



If you want to do this seriously, you need to outline the premise of what you are trying to achieve. The aims, and constraints. Also some preliminary research would be a good idea, so finding out what sort of accidents occur with buses, the injury and fatality statistics. Probably most importantly what injuries were caused.

Maybe you could explain your reasoning fr your original proposal and how you believe it would improve safety. What experience with crash safety design have you had before this?