Rolling Over

[mike-c]

i have previously said i don’t neccesarily blame a truck driver when his truck rolls over. I still stand by that as there are some really bad bends and your load can shift and a hitherto safe load just goes, maybe its shifted, maybe the load was in a container and the driver doesn’t know how its stacked or even what it is and its felt safe on his journey up untill the moment it goes. Everyone who i have spoken to has said to me they had no idea it was going to happen and they where going slow and it tipped over in slow motion. Well ,apart from one of my mates who admitted he was in a rush and just toppled it, that still didn’t stop him chasing up the company for what he called ‘unsafe stacking causing it’ and succsesfully getting himself put permanently on warehouse/forktruck dutys, which he still does now and has done ever since the last lot of roadworks finished at the Thellwall Viaduct !!
Leaving Kirkby Industrial Estate (Knowsley Industrial Park to you) the other day at junction 4 to get on the M57 i was met with this;

Blocked.

A container lorry has gone over. So, lets have a look the next day.

And here’s where he went

Mow i know that some people are going to say, lets not blame anyone until you get the facts. Maybe thats right. But here’s another fact, i would guarantee that i (and many others reading) could get a lorry and any load round that bend , every time without it going over. A few weeks previous i seen another lorry at the next junction down, he’d gone right over and well off into the verge. A few months previous a scrap metal lorry came from the M62 headed down for the docks i presume and he toppled over onto a car, that killed the lady driver that the truck ‘fell’ onto. I suppose we only hear of the ones that make the news when they block some main arterial route into or around London, courtesy of BBC radio 2, but they go over like nine pins all around the country on almost a daily basis.
I’ve also seen loads (pardon the pun) of trucks spilling their cargo recently, and all with Police attendance. I’m not sure if they get prosecuted or what.

Looks to me like fatty should have had all them straps out BEFORE his poles fell off and not after !! And here’s the coppers in attendance to make sure we’re all safe !

Well the only rolling over i intend on doing is under my duvet covers in about 20 minutes , just after i’ve made sure everything is strapped on !!!

[conor]

Mike-C:
i have previously said i don’t neccesarily blame a truck driver when his truck rolls over. I still stand by that as there are some really bad bends and your load can shift and a hitherto safe load just goes,[/img]

Disagree. It is entirely down to the driver. He is in control of the loud pedal and it is up to him to ensure he doesn’t go caning it round bends, especially if he’s unsure what’s on.

[ady1]

i noticed the other day theyve put signs on blyth rounabout saying uneven camber, seen wagon with box on its side 2/3 months ago on its side so maybe thats why.
but it amazes me how many waggons try and force there way round you or any other truck going round there, saw decker really sway from side to side on that roundabout the other day and that was all to do with the truck trying to force himself passed the decker at all costs.going round the roundabout.
if hed gone over, matey would have been long gone i suspect and everyone would have been blaming the idiot of a decker driver.
so in a lot of cases it probally is speed but unless were there who knows

[coffeeholic]

It’s not always down to speed, don’t forget the slow roll over phenomenon.

[ski]

Conor:
Disagree. It is entirely down to the driver. He is in control of the loud pedal and it is up to him to ensure he doesn’t go caning it round bends, especially if he’s unsure what’s on.

…and I wonder how many of them are too busy taking photo’s at the time…?

[edward_teller]

There was one on its side just outside Cobelfrets terminal at Immingham a week or two ago, he had driven down the ditch and flopped over on his side.

[ady1]

Coffeeholic:
It’s not always down to speed, don’t forget the slow roll over phenomenon.

whats that

[thebear]

ady1:

Coffeeholic:
It’s not always down to speed, don’t forget the slow roll over phenomenon.

whats that

Its a bit like the slow handclap

[coffeeholic]

ady1:

Coffeeholic:
It’s not always down to speed, don’t forget the slow roll over phenomenon.

whats that

Rolling over at slow speed. It has been discussed on here before, but I can’t be arsed searching for the thread, and it has also been featured in the truck magazines.

[gonzothejaffa1]

ady1:

Coffeeholic:
It’s not always down to speed, don’t forget the slow roll over phenomenon.

whats that

funnily enough excactly what it says on the tin

bumped into one of there driver’s on seaforth according to him there was 2 rollover’s on the same day one regular lad and one agency and both boxes had the same stuff in them and they were loaded top heavy with slate from mexico i think and having carried these type of boxes there are very unstable never managed to roll one though so it can be down to a number of thing’s

[mike-c]

Ski:

Conor:
Disagree. It is entirely down to the driver. He is in control of the loud pedal and it is up to him to ensure he doesn’t go caning it round bends, especially if he’s unsure what’s on.

…and I wonder how many of them are too busy taking photo’s at the time…?

Hey! Well there ya go. If i can get a truck around and take a fotograph and some numpty can’t get a truck around what does that tell ya? BTW don’t overdo the fone issue, its just the latest craze. Any fone if used sensibly is as safe as houses. Like i said before, get spotted using one and you’ll be on a name and shame website. Get caught fiddling with kids and your privacy will be respected.
When a pervert rolls a truck over you neve get to hear about it, im right, how many do you know have been done for it?
You’ll of read many report about people being caught for using mobiles fones for driving though. Logic see !!

[dieseldave]

This one’s very interesting. The way I understand it, it’s all down to physics.

Whilst a vehicle is going along in a straight line, everything is fine. There’s plenty of inertia (reluctance) in a sideways sense. When the driver wishes to change the vehicle’s direction, centrifugal (leaning) force comes into play. If the centrifugal force only just exceeds the force of inertia, then you get the slow rollover. If more speed and/or a tighter turn is involved, then the rollover is quicker and more dramatic.

Back to the straight road. The load imposed on the vehicle suspension is (normally) equal on both sides. The suspension imposes an upward force, which is distorted when travelling around a bend/corner. Road camber, vehicle speed and tightness of turn all play their part in distorting this upward force even more. Once the centre of gravity exceeds the base (whole vehicle footprint,) a rollover is inevitable. The one weapon that the driver has to prevent these conflicting forces from reaching dangerous levels is control of speed.

Yes, the movement of a load can tip a vehicle over, but anybody who starts their story at this point (IMHO) is probably being somewhat unfair. The real questions here are: What caused the load to begin to shift in the first place??
(Would that be anything to do with speed?? ) Who is the ONLY person in control of a vehicle’s speed??

So who says the things in the three paragraphs above??

1. The BOC driver training video.
2. A driver training video called “rollover” involving, amongst other experts, Pat Kennet, who has more than 40 years in the industry. Mr Kennet is/was editor of truck technology international and was also founding editor of Truck magazine.

Me?? I’m only the messenger, but I agree with Conor on this one, and the videos seem to support this. I’d like to post them on you-tube for everybody’s benefit, but I’d probably be breaching copyright. I’ve tried to provide an explanation using reputable sources of information ie, by paraphrasing the soundtracks to the two videos mentioned above. Having said all that, I do have a lot of sympathy for container drivers, because they can’t open the doors to see how it has been loaded. Go carefully guys.

[simon]

You’re right, up to a point Dave, it’s physics and speed is a factor.

Slow Roll-overs mainly involve tankers.

Driving a truck along a straight, level road at any steady speed is no problem for even the worst driver.

Put a free flowing liquid in a tank on the truck and you get a totally different animal.
As you accelerate away (from a set of lights for eg.), the inertia of the liquid causes it to effectively ‘pile up’ at the back of the tank. When you brake it ‘piles up’ at the front. When you have stopped at the next red light, the piled up liquid then moves back to being level, but that causes a wave to move to the back of the tank which bounces off the back and goes to the front, bounces off the front, ad infinitum in slowly decreasing waves until it has gained its level.
EVEN if the driver keeps their foot firmly on the brake pedal the tanker can move backwards and forwards several inches each time the wave hits the ends of the tank.
No roll over so far.
Now put a curve in the road.
Our tanker is driven down the straight road, the driver sees the curve and slows down, this sets up the wave moving backwards and forwards. The driver reaches the curve and turns the wheel to take the curve. JUST after this, the wave hits the front of the tank, but there is now an additional sideways movement. Not only has 20 odd tonnes of moving liquid hit the front of the tank, it has hit at an angle.
Modern artics, and tankers aren’t any different, have a deep king pin. That puts the front of our tank well away from the turning point, in entirely the wrong place.
Make the curve a roundabout.
If you get your timing wrong, between braking and taking the three separate turns of the roundabout, you can see how slow roll overs could happen. Add in another vehicle, possibly causing the tanker driver to brake at the wrong time and you can see that some slow roll overs are almost inevitable.
The added pressure of dead lines, late delivery penalties, getting to a suitable parking place for the night, any number of other things on your mind. Any of these could mean you miss something when deciding on your approach to a hazard.

A simple way to demonstrate this effect is to 1/2 fill a bath with water. Put your hands into the water and slosh it back and forth until you get a good wave involving most of the water rolling up and down your bath and almost sloshing over the top. Then imagine what would happen if you should pull one end of the bath sideways just as the wave is about to hit that end.

You can never fill a road tanker up to the brim. You have to allow what is called ullage. That is, free space in the tank to allow for expansion of the liquid due to heat (from cold to ambient for eg). Then different liquids have different weights for the same volume.
So you can have a tank, of say 23,000 litres volume (23 tonnes of water), plus the ullage required for that volume.
If you put 20,000 litres of a liquid in, which weighs 23,000kg, you have another 3,000 litres of empty space. That’s plenty of room for the wave to move.
(I’ve plucked these figures out of the air for illustration purposes)

[spardo]

Now I know there are some liquids that you just can’t baffle (doesn’t it turn milk to cheese or something ), but apart from that don’t tankers have baffles to combat that very problem?
If this question sounds naive but obvious to some, it is because bulk liquids is one of the only 2 areas of road transport that I’ve no experience of (the other being bulk cars ).

Having said that, I do know that the phenomenon of slow rollovers (like unexplained wheel loss) has baffled (sorry) experts for years and I’m not sure even now there is a definitive answer. It has something to do with a slight shift in weight (not necessarily load) to one side followed by a similar slight (and normally safe) shift in the opposite direction. Entering and leaving a roundabout is a classic example. The return from the first shift augments the second one to create an unexpected extra force.
This can happen at very low speeds as I have experienced once myself. Seeing the nearside trailer (but not the tractor) wheels lift on leaving a roundabout with an empty container on board is a sobering occurrence. It didn’t go over, it never has, but it could so easily have done.

Now many would say, and have, that an experienced driver should foresee these things and there is some justification for that. But variables such as wind, road camber and suspension (many modern drivers do not drive the same vehicle every day) can conspire to foil an expert.

Finally, is it possible that modern soft cab suspensions fool a driver into a false sense of security once he has got used to the rolling motion? I know it is an extreme example, but wouldn’t you brick it the first time in a Magnum after habitually driving a Borderer

[simon]

Spardo:
don’t tankers have baffles to combat that very problem?

I’m a bit out of date on tankers now mate, but yes, most do have baffles, if not separate pots, which helps a lot but doesn’t stop it entirely.

Those big waste tankers you see, with pumps and all sorts of stuff fitted, are just one big barrel though. As they are often used to shift sludge, which can separate out and then be almost impossible to clean the solids out from around the baffles.
I think that it’s also to totally remove any possibility of the slightest residue from a previous load coming into contact with the next one. They might react with each other with disastrous consequences.

I’ve been away from tanks for quite some time, and didn’t spend that much time on them then. This is mainly what I’ve picked up over the years from having a general interest.
(MMTM )

[dieseldave]

THIS POST HAS GOT EVEN MORE INTERESTING!!

Now tankers have been mentioned, I agree with both Spardo and Simon on all points, including cheesemaking and deep pins.
I’d add that the phenomenon now being discussed is known as “lateral surge.” As noted, neither baffles nor compartments can counteract lateral surge, since they’re only useful in counteracting fore and aft surge. According to the videos, it’s still a question of speed, camber and tightness of turn and it’s also the same physics for tankers that when the centre of gravity exceeds the base, the vehicle will fall over. With a partly loaded tanker, in certain circumstances, the amount of provocation needed to roll it over can be very small indeed. The videos I mentioned seem to be quite clear that a rollover is always speed-related and that it’s the driver who controls the speed. Since the people who made the videos have qualifications that I don’t even know what the initials stand for , and since the videos are ultimately approved by the DfT, I let them speak for themselves.

Since tankers commonly carry nasty “stuff,” ADR then takes an interest and has come up with a rule that I call the 80/20 rule. Paraphrasing all the technical and legalistic mumbo-jumbo out of it, which is very dense and about as dry as a Ryvita, 80/20 relates only to ADR tankers and goes something like this:

IF a tank, or a compartment of a tank is greater than 7,500 litres capacity and has no baffles, then the following applies: It can’t legally be driven on a road if the liquid level is above 20% but not above 80%. Or in other words, the forbidden fill-level zone is between 20% and 80% on that type of tank. In the UK, that applies to a dangerous goods tanker, when the TANK is manufactured on or after 10/05/2004. It does seem to be aimed at keeping potential product movement to a minimum, but given Simon’s noting of product expansion and contraction, I wonder how enforceable it is in practice?

If you glance at a fuel tanker making a delivery to a petrol station, you might notice that the compartment sizes are usually written somewhere on the tanker. You might also notice that the largest compartment size is probably 7,500 litres. That gets them neatly around the 80/20 thing, because 80/20 then doesn’t apply at any stage.

[bikemonkey]

Picked up a heavy 20’ box out of freightliner Manchester for Runcorn 2 weeks ago.
It was swaying all the way down Westinghouse rd in Trafford park.made me bum go a bit tight,phoned the office and told them to sort of cover my arse and drove gingerly over to Runcorn.

I never know what to do though as obviously you dont know how the box is loaded.
After all you cant go refusing to drive anything that feels a bit wrong,you just have to drive accordingly and hope for the best

[scania245]

on unbaffled tankers you can encounter the washing mashine effect 50% full being the worst ie heavy braking at a severe bend causes the load to first go forward then back then up the side of the tank as youre going round a bend and yes i have been muppet enough to have experienced it you really dont want to try it iv also had the rear axcles on tanker trailers lift going round corners still didnt belevie what i saw as for shifting normal loads how many drivers check there straps after 5 minutes driving then another couple off times on route not many (its not what theve been taught ) but the security seal doesnt help me i check the load restraints when ever i stop (just hate picking things up) but my prsonal opinion on most rollovers is to much speed

[Lucy]

bikemonkey:
Picked up a heavy 20’ box out of freightliner Manchester for Runcorn 2 weeks ago.
It was swaying all the way down Westinghouse rd in Trafford park.made me bum go a bit tight,phoned the office and told them to sort of cover my arse and drove gingerly over to Runcorn.

I never know what to do though as obviously you dont know how the box is loaded.
After all you cant go refusing to drive anything that feels a bit wrong,you just have to drive accordingly and hope for the best

That’s why so many decent container firms are fussy about who they take on for some jobs. It isn’t always as simple as people think, being a box jockey - why do you think so many of them are the subject of Sally Traffic’s reports?

Our lot are just expanding by nearly 50%, and they are only advertising amongst their own staff and subbies for known drivers with known and proveable experience. They simply won’t take anyone else on, despite the number who would like to join. Too risky.

[Lucy]

scania245:
on unbaffled tankers you can encounter the washing mashine effect 50% full being the worst ie heavy braking at a severe bend causes the load to first go forward then back then up the side of the tank as youre going round a bend and yes i have been muppet enough to have experienced it you really dont want to try it iv also had the rear axcles on tanker trailers lift going round corners still didnt belevie what i saw as for shifting normal loads how many drivers check there straps after 5 minutes driving then another couple off times on route not many (its not what theve been taught ) but the security seal doesnt help me i check the load restraints when ever i stop (just hate picking things up) but my prsonal opinion on most rollovers is to much speed

How does that account for the known phenomenom (sp LOL) of slow-speed rollover then?