Yeah, me too....
School buses aren't all that safe, but the Abrams tank is.


A regular tank

Or a wheeled tank

In the first picture, the student driver overlooked that the tank had the right of way - but still walked away. In the second accident, the driver wasn't as lucky.

 

The Chevy avalanche in all forms is BOF. The ridge line is weaker than a comparable weight BOF truck and is outperformed in all ways by one in terms of specs and towing performance from behind the wheel. A frame for the same weight of vehicle is strait up stronger. Period. Unibody is only practical below 4500lb due to superior cost savings and way easier manufacturing with modern methods, above that weight limit BOF is stronger, more capable, more affordable, and just plain better.

 

How about this one:

https://www.thedrive.com/news/31217/...n-mining-truck

 

Striker223- The 2005 NHTSA gives the Avalanche a 3 star Front Drivers Side rating and 3 start Roll-Over rating. Side crash test was left out. I could not find any recent crash tests although I did see a 5 star front crash score on the 2009 model- with the same poor Roll-Over score. I would be curious to know how they could possibly achieve a 5 star Frontal rating in a BOF for 2009. I also highly question the validity of it since there have not been any more recent, credible tests like IIHS. I also doubt any major changes were made to the structure- but I could be wrong about that.

I agree with you that a BOF is typically "stronger" in some ways than your typical and comparable uni-body but that really was not the focus of my question- relative safety was. Again, I agree that if you need to TOW, Haul heavy things, have superior off-road, 4x4 prowess and isolate noise to the cabin, BOD will win out 99-100 times- everyone knows this.

I disagree that the "practical" limit for a strong uni-body is 4,500- what makes that so? The 2019 MB GLE's e.g., are ~5,000 and plenty strong- AND achieve Top Safety Pick "PLUS" which speaks volumes.

Also, as others illustrated, a tank is technically a uni-body (no frame). The M1 weights a mere 60 tons or 120,000 lbs. That exceeds your 4,500 limit. It all comes down to design and how the manufacturer chooses to reinforce and use the materials. Simply being a uni-body, by itself does not by itself make a vehicle less strong.

I also disagree that a complex uni-body design is "way easier to manufacture." Uni-bodies rely on technical CAD-CAM analysis with tight tolerances which need to be measured during the manufacturing process; hundreds of robotic welds, carefully designed and tested crumple zones that require the manufacturing and assembly of different materials in different areas, etc. Compared to bolting a body on a metal frame, there is no comparison. Uni-body is far more complex- and in my mind, far superior when it comes to safety. BOF is decades old technology- that said, it does still have it's uses and is to quote you, "BETTER" for certain types of usage. That said, uni-body is also "BETTER" for the typical daily driver that doesn't tow much or haul heavy loads or do serious 4x4 off-road driving.

Getting back to the focus of this thread- SAFETY, let's look at a Whiplash analogy...
Body on Frame- You are sitting in a chair with a 2x4 up against the top of your back. 200" away (length of vehicle) someone slams that 2x4 with a sledgehammer. You are going to feel nearly the full force of the impact.
Uni-body- You are sitting in the same chair, only key parts of that 2x4 are made of paper mache that crumble very easily and give. You will still feel some impact but it will be highly mitigated thanks to those crumple zones.

The above makes my point ONLY from the perspective of SAFETY. You make valid points, but from the perspective of UTILITY. Both arguments are valid in their own rights. For my personal needs, a uni-body is what I need.
All of this said, where I struggled and still do, is that I really like the heft of a 6,000lb. vehicle. Even from a safety perspective, I think that vehicle would fair well in several scenarios, against, even a well rated 5 start vehicle that is only 2/3rds it's weight (many SUV's are only around 4,000lbs) especially in a side impact or head on scenario. My compromise is the 2020 MB GLE350 which is still nearly 5,000lbs., and 5 star crash rated uni-body. All this said, the best safety system is the driver. Paying attention, staying a very safe distance behind the car in front of you, not passing on the right or getting distracted (texting) is key.

 

Okay. If you really want to understand safety than take high school level physics and tell me what happens when two masses interact and one is 30% heavier than the other. What object will accelerate more? If you head on two objects of dissimilar mass the lighter one will be sent to ZERO then have velocity in the opposite direction while the heavy one will not even completely stop moving.

You tell me what cars occupants experienced greater peak forces. A three star vehicle ONLY 500LB MORE mass than a 5 star will plow THROUGH the 5 star. It's physics and unavoidable, in all the safety tests the rating is ONLY relative to things in the same weight class. Do the math for a 2800lb 5 start rated mini couper vs a 9000lb 3 star Ford F-350 Diesel and tell me who experiences greater forces.

I have never seen a situation NOT involving a fixed object and nothing else where a unibody does better in terms of occupants vs a BOF since the latter nearly always has a 1500lb weight advantage and you need to accept that more mass OVERRIDES the crumple advantage of a unibody. All the crash tests you see done to BOF cars show all the force of the car (do the math yourself) vs usually one framerail if not just the outer corner. Now take any of your favorite unibody cars and do the math how much it takes from its own weight in that same test now ADD the difference from weight and you will start to see that in a real crash the BOF car will see not only less overall force than if it hit a wall since that simulates it hitting itself (it has a 1500lb weight advantage vs most unibody stuff) so now the force it has to deal with is way less and you see the result like my accident where my BOF car took less than it "should" have based off testing and the unibody "somehow" took way more than it did during its testing.

If you are so concerned about whiplash than pick something that will NOT zero out motion vs something that WILL ZERO INSTANTLY then move in the opposite direction. Crumple zones on BOF vehicles are not as good sure, but they also get to use the other LIGTER car as their crumple zone while the light one is screwed due to physics.

If you want the ultimate get the Toyota sequoia that has a perfect ZERO fatality rate.

The 4500 limit is directly due to the fact that unibody structure in a non-monocoque (skin is the structural member like a tank) is trying to mimic the rail structure of a frame to have enough repeat load strength and flex resistance to allow towing and carrying weight and is simply not as good pound for pound. The GLK you mentioned (I have worked on and have 3 as regular customers) are heavy as hell due to the need for massive amounts of reinforcement to reach the same strength as BOF vehicle of the same size and the same weight F-150 totally outclasses it for all load and flex metrics. It's WAY cheaper to make a unibody since you cut out an entire line in a factory and no longer have to mate the frame to body after taking time to install the driveline and everything else. A unibody car has two "pods" that you can quickly (literally, for a lot of stuff I drop the front subframe) remove or much more quickly insert (like on a line) that contains the entire "car". Ever wonder why suspension carriers exist any they don't just mount directly to the unibody? They tried this and found the amount of reinforcement needed was very heavy vs just putting a boxed metal carrier for the suspension to work against.

 

Heres another way to put it, if you removed the cab off my 2017 ram AND ONLY THE CAB, and attached a little carrier subframe with a engine and wheels to the front and then a bar in the back with two more wheels you have created a 2011 Honda Civic. Crash said cab into a wall and it will do great! Very light so very little force involved overall. Now ram that same assembly into a normal truck and tell me how that 2500lb weight difference goes. Newer BOF vehicles when you are under them and looking around literally have mini-unibody rails and cross supports just like some entire cars in addition to the massive frame to help further improve stiffness and support the frame and take impacts.

I will go out of my way and show you this fact Monday with I'm in the shop and I'll throw some stuff in the air so you can see it. The extra weight in a BOF vehicle literally comes from attaching a boxed steel structure to a unibody upper shell.

Crash tests would be far and above superior to how it's done now if they rated each vehicle vs a standard impact force in addition to existing force testing. Aka using a Chevy equinox as a ramming target with both it and the test subject going 40 at each other and the same test with a 2500 truck but that gets expensive in a hurry and will totally ruin the safety image of a lot of vehicles,

 

Striker- Your conclusions are simply irrelevant on many levels. To begin, not only have I taken HS physics- but studied Engineering in college as well. Whiplash is a real concern and likely happens more than head on collisions. Also, you rule out crashes into a fixed object too- in an attempt to support and validate your point. I never denied that a big, heavy mass traveling at speed will have some inherent advantages over a smaller vehicle- that's pretty obvious and I have stated that several times. That said, I don't consider the delta between a 5,000lb. GLE and a 5,800lb. BOF vehicle all that significant. 5000 vs 5800 is not 30%. I would not chose an SUV that is under 4,000lbs. regardless of it's construction. Comparing a 2,800 lb. mini-cooper to a 9,000lb Ff-350 is an extreme example, and again skewed to make your point. In reality, you are taking about a 1-2,000lb. difference. I agree, that is still significant but so are crumple zones among vehicles of similar mass. I also heard of a story where someone in a Honda Accord survived and a Hummer driver did not. Design matters- stability (not rolling over) matters.

You completely, and conveniently ignore (to your advantage), many scenarios that would favor the uni-body vehicle. Included is the fact that most (not all) typical accidents will be between vehicles of similar weight simply due to the fact that the vast majority of daily driver vehicles manufactured weight between 3,000-4,000lbs. Some of the scenarios your conveniently ignore, that would favor a uni-body design, to name only a few include: vastly superior accident avoidance, superior handling/agility, far more safety systems, vastly superior braking performance (shorter) over trying to stop a 6,000-8,000lb. BOF 60-0. Last but not least, most uni-body vehicles will have far superior Roll-Over ratings. Making an argument based only on your exaggerated scenario of the heavier vehicle "plowing through the smaller vehicle" is very short-sided. I will conceded that you are in fact correct- about that one scenario, however why did you conveniently ignore all the other points that favor the uni-body design. Surely they could be explained by your HS physics class.

Regarding the IIHS data, I suggest you re-read it a little more carefully. It is based on "reported" fatalities per 1 million. It does not say there have been 0 fatalities period. Also, the Sequoia is likely used as a daily driver as much as many other uni-body SUV's which can skew the data. It has a more utilitarian purpose.

"If you are so concerned about whiplash than pick something that will NOT zero out motion vs something that WILL ZERO INSTANTLY then move in the opposite direction. Crumple zones on BOF vehicles are not as good sure, but they also get to use the other LIGTER car as their crumple zone while the light one is screwed due to physics."
***YOU MAKE A VERY VALID POINT HERE. I don't have all the answers, which is why I posted this thread- to learn. Regardless of some of our differing opinions, thanks for sharing your thoughts. You make some good points.

 

I think there is something to your point. I have also seen some newer (although very few) BOF vehicles that did well in crash tests. To your point, I think a great example is the new 2019-2020 Dodge Ram 1500 is a Top Safety Pick +. Due to the strategic use of high strength steel, carbon fiber, aluminum, etc., it weights relatively less than some competitors- between 4,798-5,372lbs. I would not go so far as to say the frame has true crumple zones but it does employ a useful mix of materials of varying strength e.g., high strength steel, aluminum, ferrite bainite, multi-phase advanced high strength steel, etc. It's a winning design and the crash tests do not lie. Where I have the biggest issue is with true BOF vehicles where crash test scores are hidden from us. Believe me, if they told a good story, we would know about it (good for sales).

The Honda Ridgeline is also a Top Safety Pick BUT it is uni-body. Note: They don't typically test for rear end collisions. I imagine they would do poorly.

All things (weight) being equal, I would still go uni-body for my daily driver, mostly highway use. That said, I'll conceded that some newer BOF are probably leveraging some new design features to make them relatively "better." I also do like the weight factor- as you said, you can't get around physics. One other thing I wrestle with is the fact that you will have a ton of weight behind the cab in a big truck- going into a fixed object, that can't be particularly good. For heavy towing, hauling a lot of weight, ,4x4 off-road, BOF all day long. BOF has a clear purpose and it excels at it. For my needs, it is simply not the better solution.

 

Im glad you are listening, I intentionally used over simple and extreme examples purely to help drive the point home and actually I think the sequoia is a true zero vehicle and even though it's used as a daily it doesn't change the fact that out on the road if crashed that on average it will be vs something 2000lb lighter and be way ahead.

Rollover and handling all depends, I work on a lot of cars and have a very interesting test route near my shop that I detailed in another post I'll link and you would be amazed how well modern (2015 and up) large patten trucks and SUVs do in turns and braking in particular is on par if not better than cars because everything is scaled up to match these days not like before when a truck was just more weight on the same braking system. It's older ill maintained crap that acts like boats that seem to want to roll over at the lightest maneuvers but then again my LS430 is an absolute boat vs my truck in turns and I can't push it as hard so it not dependent on just body style. Plus to be fair you did say you want an SUV anyway so handling will be inferior to a longer wheelbase or lower vehicle anyway assuming both are sprung exactly the same and have exactly the same roll rate sway bars. Most of the time this is not the case and stuff that is taller get more aggressive springing to counter this, there is a major difference in what the car can actually hold in a turn vs what feels good to the driver. Best case in point is a 2015 civic I did struts on and was sending through the hairpins to make sure all was well and it would not roll or feel bad but it under-steered and lost traction 10mph lower than a 2011 sequoia that FELT like it was gonna tip over but actually was able to hold the turn way better despite not feeling as good. Same story if I bring my modded 2003 ram into the same area vs a 2010 mustang or 2013 BMW 3 series, it shouldn't beat them but it does due to ultra aggressive springing and 400% stiffer roll bars that allow the 305s to hold the road. The cost is a hilariously firm ride and if you move it at all off center you can feel the bars load up and once you come back it basically whips back to centered in a way that would have comfort engineers cringing. You can't have both a seriously good ride with little shock and whip and high performance at the same time, you need to pick and even though a lot of modern stuff does well with adjustable suspension/bars/damping whatever when you increase the amount of mass in a larger car these systems are less impactful. You also need to keep in mind if your car is set for comfort and you need to dodge something right NOW you will not have the handling and response it would have in other modes unless you leave it in the best one at all times.

I wholeheartedly agree avoidance is best and that comes in several ways and if you are driving something that doesn't have ability (power, brakes, turning, etc) you need to adjust for its weakpoints. My LS430 has power, reasonable brakes, but horrible handling, reaction, and roll stability so I intentionally make sure I have extra lateral spacing and room when merging so I do not have to perform a rapid action but I have power and brakes so my front to back spacing is not as aggressive as it would be if I'm in something that lacks those.

Oh and lastly every single sequoia I have seen is a daily usually driven by a woman.

 

All good points- especially about the under-steer dynamics and feel vs. reality. Mid-engine sports cars come to mind. Though not RE, my friend has a Viper- handles ok, but when she let's go, it's all over the road. That combined with 600HP is a dangerous combination. I suspect the new Corvette will be much of the same. I have watched numerous videos where sports cars, even going in a straight line just seem to lose it when rear-biased torque push them outside of their safe operating limits- can happen at even high speeds. That said, a sports car will likely be far easier to recover (counter steer, drifting) than e.g., your LS430. Also, we can both cite extreme scenarios to support our points, myself included, but I look at patterns. In general, I sincerely do not think on average (with perhaps some exceptions e.g., maybe a performance designed Dodge SRT-1- Viper Truck), large, heavy BOF truck will match a car for braking and roll-over resistance- beefed up components or not. That said, you know your vehicles and continue to make excellent points.

 

Consider that a Viper (I've driven a 4th and 5th gen) will let go all at once like you said but it takes about 3x the speed as a normal car to get there lol! Driven the same speeds it is ungodly stable. The SRT-10 truck is a fun one and the vehicle I targeted when modifying my truck but I ended up exceeding it. I've to date never driven anything that comes remotely close to what a 5th gen viper can do at a given speed.

I get to drive a huge spread of cars in various states of repair due to my job so my bias doesn't really play into this since I can literally tell you from personal experience how things feel AND hold through serious turns. Audi is the best on average, merc is boat like and gives a false sense of weight and confidence in the SUVs, BMW is literally all over the place depending on year and model, Chevy cars are softer feeling but usually outperform their analogues in terms of how fast you can actually go and maneuver, same with dodge but they actually feel good and talk to you well, jap cars generally feel very "light" and talk to you a lot but don't do so great when pushed hard and Lexus in particular is very very nice when not pushed and falls apart when trying to get into it.

The fact is the vs most cars and "suv" things I drive the large US made BOF stuff just does better even though they don't feel confident doing it. RWD consistently is better than fwd and Audi nails it in terms of dynamics across all their SUVs and cars. Most "normal" cars do not stop as well as a BOF truck even if you push them to ABS and confidence and predicability is just not as good on ones that have even 40 miles while I have found trucks to remain more consistent even at 300k miles.

There have been very few cars I'm actually impressed by objectively, in that they do way better than average and overall perform well/better than I thought they would.

S class and select E class, any Audi, M cars and older 3 series, Porsche anything, any RWD dodge or Chevy car, any corvette, RWD Cadillac's, weirdly enough mini coopers, Ford SUVs (again weirdly), Chevy trucks that are below 200k, and dodge trucks 4th and 5th gen only. Toyotas do not do well and their trucks and SUVs are worse than I expected but the Lexus LX570 and LX470 both did way better than I expected and actually had me mentally comparing them to a Durango or grand Cherokee V8 at times even though the latter is on par with a base Porsche SUV.

May I suggest you test drive a Q7 and X7 as well as a 5th gen ram without air suspension? The ram may seem like an odd recommendation but it's in the same price range and has the same features as the others sans some interior material quality that's all. Also consider a grand Cherokee or Durango SRT versions since they drive very very well beyond the euro options. But those are smaller than you want but are unibody and they are 5500lb

 

A vehicle with a lower center of gravity, good weight balance, dialed in suspension and least we not forget, excellent tires will do the best. This is why you typically don't see trucks in the lineup at the Indianapolis 500- sans the NASCAR Truck series but I would argue those "trucks" have more in common with cars. Indy cars are about an inch off the ground- super stiff suspension and very sticky tires. Opinions are nice- but also subjective. Ultimately, you can't get around physics.

 

Yes. That's why modern trucks and SUVs do so much better than cheap cars, they have muh larger tires and relative centers of gravity (vs track width) are very good these days. Test drive the stuff I mentioned in my last post since I think you will like something off that list and all will crash extremely well.