How hard is it to disable or adjust a seat belt load limiter to improve safety?

I just learned about the potentially awful things called seat belt load limiters, and I would like to know if they can be disabled or adjusted. I’m most interested in Toyotas. Even information on how strong the load limiters are would be good. Load limiters are a good idea if the load limit could be adjusted based on the health, age, and size of the occupant. No car that I know of lets you adjust the strength of the load limiters let alone do they even mention that it exists. It is an important feature for an elderly frail person in a mild or moderate accident, but I am the opposite of this.

I saw one of those old versus new crashes where they crashed a Kia Rio in to an older car. The high speed camera shows the seat belt in the Rio pulling out and the crash dummy moving forward and almost touching the steering wheel. I learned what load limiters are and realized that this doesn’t leave any room for safety in a higher speed crash. Recently this video came out and it shows the horror that results in a 50 MPH crash in a vehicle that has a seat belt load limiter that is optimized for a 40 MPH IIHS crash test. The dummy moves far forward and makes hard contact with the steering wheel in the neck and head area. They say it would be severe brain and neck injury and likely fatal. Watch the Honda CR-V 50 MPH and 56 MPH horror crash test here: Crash Test | 40mph VS. 56mph | How Speed Affects the Severity of Crashes - YouTube

The load limiter is likely not just for chest compression reduction, it probably helps control the rebound of the body and head of a crash test dummy in the IIHS crash test, so the dummy’s head doesn’t hit the B pillar on the way back and get a lower score on the test due to a non life threatening injury. Cars without load limiters still achieved Acceptable ratings on IIHS crash tests at 40% and 40MPH in to a deformable barrier. I believe IIHS testing has created an unrealistic goal of no injuries in a severe crash, and auto makers have optimized their restraint systems for this test even though it results in a higher risk of fatality for the driver and passengers in other types of crashes or at higher speeds especially those who have stronger and less frail bodies.

If you want to know if your vehicles has load limiters or pretensioners you can see page 43 of this document: Page 36 shows that load limiters help increase safety for people weighing over 175 pounds cars, but the reverse is true for minivans.

Pretty certain there’s nothing you can, or should, do to fiddle with your seatbelts. There’s about twice the energy in a 56 mph crash compared to a 40 mph crash, so it’s no surprise that it’s more severe. The airbag helps, so this is one of those ‘why worry about it’ things, to me.


Invisible Snowman - if it is invisable how do you know it is a Snowman ?


I would be interested in seeing the credentials from @InvisibleSnowman, such as mechanical engineering, automotive engineering, physics degrees etc. Perhaps copies of any peer reviewed papers he published regarding automotive safety.

I think auto manufacturers, NHTSA and other competent organizations having jurisdiction, address these issues and optimize seat belts, air bags and crumple zones for the best occupant protection.


OK , I just did a few minutes of bargain basement research on Google about seat belt load limiters. Mr. Snowman needs a Hobby because I could not find anything about them to worry about .


When you walk by it gets very cold!

Anyway, I wish that the people who had the you don’t need to wear a seat belt mentality in the 1970s and 80s, which was like half the US population, would refrain from expressing their opinions in this safety discussion. If you don’t know the answer that’s fine. Saying I shouldn’t mess with it, or that I am less qualified than the car makers to watch out for my own safety isn’t what this is about. It’s very fortunate that AAA did this crash test so I can demonstrate is what is obvious and logical to me even before I came across this 50 MPH test. It is extremely rare for a test like this to be done. Volvo does it knowing that their cars are already designed to handle it. Even (youtube channel: ) which does a variety of more extreme crashes doesn’t do this test.

Did we acquire another \\TROLL////?


I find it funny that your name suggests that you drive one of the few vehicles that is actually crash tested at higher speeds, and would have load limiters designed for these crashes, but you claim that this safety issue doesn’t matter.

I did not know about load limiters thanks for the info. I see them as a good idea to lessen seat belt injuries, as long as the airbag goes off.

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It is logical and obvious that a crash at higher speed will be more damaging than one at lower speed, and therefore more likely to cause injury. It is not at all obvious that there is some nefarious manipulation of the ‘seat belt load limiter’ to improve automakers crash test scores, as you are claiming. And it is pretty much a fact that there is nothing that your, me, or any other individual can do to ‘improve’ the performance of the seat belt system in our cars. Plenty of opportunity to screw it up, though!


It sounds like the OP is like many others who believe the hype about new cars being safer that if you ever get into a wreck it will just be like bouncing around in one of the bouncy things at the county fair and you may be shook up but not hurt.

I think the OP is forgetting that ANY design of the safety systems of a car will be a compromise. The design cannot be optimized for a specific accident and for a specific occupant. Thus, a whole lot of expertise and testing dollars have been spent by each manufacturer and by IIHS testing to find many different answers to the question of what is the best compromise. Improving the 50 mph head-on collision might degrade the quality of the 30 mph T-bone. So, instead of trying to be smarter than the experts and modifying your car, it would be better to decide exactly which IIHS test do you want your car to pass with the highest rating, and then purchase the winning vehicle. My own personal choice is accident avoidance (rather than having a wonderful collision) so I particularly want blind-spot monitoring, and my next car will have it.


Agree that is the best way whenever posable.

I think the nhtsa has an excellent study on pretensioners and load limiters.
I also think @InvisibleSnowman has got the idea of how they work all wrong.


Good find, here’s the abstract, I put the important part in bold for the benefit of the OP:

“Pretensioners and load limiters are technologies designed to make seat belts more effective. Pretensioners retract the seat belt to remove excess slack almost instantly upon sensing the vehicle has crashed. Load limiters allow the belt to “give” or yield when forces on the belt rise above a predetermined level. NHTSA has long encouraged – but never required – installation of these technologies in the front seats of vehicles. By model year 2008, all new cars and LTVs sold in the United States were equipped with pretensioners and load limiters at the driver’s and right-front passenger’s seats. Double-pair comparison analyses of FARS data for 1986 to 2011 compare the fatality-reducing effectiveness of seat belts with and without pretensioners and load limiters at those seats. In passenger cars, CUVs, and minivans, a belted driver or right-front passenger has an estimated 12.8 percent lower fatality risk if the belt is equipped with a pretensioner and a load limiter than if it is not equipped with either (95% confidence bounds: 2.6% to 23.0%). By contrast, the analyses of the currently available data do not yet show a significant effect for pretensioners and load limiters in truckbased LTVs (pickup trucks, SUVs with body-and-frame construction, and full-sized vans); it may be advisable to rerun the analyses in about 4 or 5 years when more data will be available.”

Just to add my 2 cents, I think they should make breakaway center consoles, and seat belts that can react to side impacts. 1 dead, 2 with broken hips due to side or tbone accidents, and others with whiplash or other trauma.

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That’s exactly what you want to happen. It’s a complete myth that everything remaining rigid during a crash is the least likely to cause injury. What you really want is for your body to be slowed down over the maximum possible distance, so that the deceleration is as gentle as possible.

It reminds me of that scene in Superman - the good one, with Christopher Reeve (yeah, I’m dating myself). Lois is falling, and Supe dashes down and catches her about a foot above the ground. She slams into his arms and is perfectly fine.

In reality, she’d be dead. What Clark needed to do was to catch her earlier and then gradually slow her down. Slamming into the Man of Steel at high speed isn’t going to be any better than slamming into the pavement at high speed.

So yeah, maybe that load limiter ends up making you hit the steering wheel. But that involves several variables. First, where’s the airbag? The airbag system “knows” what the load limiter is set to, and if it detects that the crash will cause you to impact the steering wheel, it will fire the airbag to cushion that blow. Second, it’s better to hit the steering wheel after having been slowed down over a distance than it is to “hit” the rigid seat belt after no deceleration at all.


The real Superman was George Reeves, the real Batman was Adam West, the real Batmobile was the one Adam West drove.
In the old movie serials, a pre-war Batman had (unknown brand to me) phaeton, a post-war Batman had a ‘49 Mercury convertible.
To stay on thread subject, none of these had seatbelts.

Am I dating myself?


I figure that the load limiter cause the following effects:
With a load limiter:
40 MPH moderate overlap: no injuries
40 MPH full overlap: unknown, possible contact with steering wheel. NHTSA tests at 35 MPH, 40 MPH has 1.31 times as much energy.
50 MPH moderate overlap: severe and possibly fatal upper body injuries in many vehicles for the average person, healthy or unhealthy, overweight or not, due to contact with steering wheel. Minor to moderate injuries in a Volvo for a healthy person. Does anyone want to find the crash test dummy data for the Volvo XC90 50 MPH moderate overlap test?

With a stronger load limiter or without one in a full size car it would likely be like this:
40 MPH moderate overlap: Minor injuries due to head rebound and seat belt compression. Possibly serious injuries for a elderly frail person or an obese person, maybe even fatal.
40 MPH full overlap: Minor or moderate injuries from seat belt
chest compression depending on the person. Possibly fatal for a on elderly frail or obese person.
50 MPH moderate overlap: Minor or moderate injuries for a healthy person who is not overweight. Moderate or serous injuries for the average person. Most likely fatal for an elderly or obese person.

It looks like they’re designing the restraint system with overweight people in mind. Should a car that I drive be less safe for me because so many other people are fat and unhealthy? Here is a study showing a increase in accident fatalities due to being overweight. These studies are often flawed because they don’t take in to account different driving habits or vehicle types driven by different people, but there is still some good in them. Here it is Obesity and Risk for Death Due to Motor Vehicle Crashes

Here is the 2010 Honda CR-V NHTSA data for the 35 MPH full overlap crash test: . On page B-9 it shows the peak chest deceleration of the dummy at 35g! That means if someone is 30 pounds overweight in the chest area, that their body will be exposed to up to 1050 more pounds in an accident!

I’m not saying load limiters make things worse in 40 MPH accidents. I’m saying that they make it worse at higher speed crashes, especially involving bigger boned taller people who are NOT overweight. Wouldn’t having minor injuries at 40 MPH and moderate injuries at 50 MPH be better than having no injuries at 40 MPH but fatal injuries at 50 MPH? I know what I would pick.

Please let us know any facts that support your claims.