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I'm disappointed in the 2021 Sienna frontal crash test scores. I bought before the NHTSA published their ratings, but was happy with the Good performance in the IIHS tests. I estimated the worst-case would be that the driver or passenger would be 4-star.

The previous gen Sienna had a 5-star and 4-star rating for the driver and passenger, respectively. The 2021 dropped to 3-star for the driver; the passenger is still 4-star. For comparison, the latest Odyssey, Pacifica, and Sedona all achieved 5-star frontal ratings for driver and passenger.

Toyota has a surprising number of vehicles that have a 4-star (or even 3) for driver OR passenger. They should do better.
 

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I'm disappointed in the 2021 Sienna frontal crash test scores. I bought before the NHTSA published their ratings, but was happy with the Good performance in the IIHS tests. I estimated the worst-case would be that the driver or passenger would be 4-star.

The previous gen Sienna had a 5-star and 4-star rating for the driver and passenger, respectively. The 2021 dropped to 3-star for the driver; the passenger is still 4-star. For comparison, the latest Odyssey, Pacifica, and Sedona all achieved 5-star frontal ratings for driver and passenger.

Toyota has a surprising number of vehicles that have a 4-star (or even 3) for driver OR passenger. They should do better.
Driver may die, But those in the rear will survive with those non removable seats.
 

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I’ll take my chances with the Toyota. The odds of a fatal accident are significantly less than having a clunker from Pugeot Fiat Chrysler or a bad transmission from Honda.

One of my other vehicles is a Harley Softail Slim, It is much worse in accident testing.

If safety is your highest concern you may want to sacrifice gas mileage and go with a large SUV as the mini van ratings are not far off each other.
 

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I'm sure the 2021 Sienna is "safe", but that's not the point. Relative to other vehicles it's size, the front crash test results from the NHTSA are not great. They're not even good. As I mentioned on the other thread, Nissan got 2 stars on the front driver crash test and retroactively fixed EXISTING vehicles, so it's safe to say that 2 stars on that test is "failing". 3 stars is, at best, barely passing.

In my opinion, there's no way Toyota designed this vehicle to get 3 stars on a driver crash test. As many of you have pointed out, Toyota is proactively taking away the ability to remove the 2nd row to excel on a FUTURE safety test. It seems almost impossible that they would design a brand new vehicle to get a barely passing score on the most common front driver crash test. Without knowing more, something is either wrong with the NHTSA test or there is a specific failure on the vehicle that likely should be corrected.

I can't explain how the Sienna aced the IIHS tests and then got this result on NHTSA driver's test. Maybe someone with more knowledge of the actual tests could help explain that.
 

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I'm sure the 2021 Sienna is "safe", but that's not the point. Relative to other vehicles it's size, the front crash test results from the NHTSA are not great. They're not even good. As I mentioned on the other thread, Nissan got 2 stars on the front driver crash test and retroactively fixed EXISTING vehicles, so it's safe to say that 2 stars on that test is "failing". 3 stars is, at best, barely passing.

In my opinion, there's no way Toyota designed this vehicle to get 3 stars on a driver crash test. As many of you have pointed out, Toyota is proactively taking away the ability to remove the 2nd row to excel on a FUTURE safety test. It seems almost impossible that they would design a brand new vehicle to get a barely passing score on the most common front driver crash test. Without knowing more, something is either wrong with the NHTSA test or there is a specific failure on the vehicle that likely should be corrected.

I can't explain how the Sienna aced the IIHS tests and then got this result on NHTSA driver's test. Maybe someone with more knowledge of the actual tests could help explain that.
The IIHS tests are harder to pass because they occur at a higher speed and involve only a portion of the front of the car.

The NHTSA test is a 35 mile per hour impact into a wall. The entire front end structure of the car is involved in dissipating the energy of the crash. This test is analogous to either hitting a concrete wall with zero compliance at 35 miles per hour or hitting another car of similar mass traveling in the opposite direction at the same speed where the front ends of both cars are aligned perfectly (as if both cars were driving in the same lane but in opposite directions). This is not representative of a lot of real world accidents, where the vehicles are not meeting perfectly head-on.

The IIHS tests are a 40 mph impact into an offset barrier. Only 40% of the front of the car impacts the barrier during the offset crash test. The small offset test only impacts 25% of the barrier. These tests are more difficult to pass, as a much smaller portion of the front end crash structure must dissipate the crash energy from a higher speed collision.

During an impact, the car is designed to crumple in a controlled manner. This is a bit of a simplification, but the more length of the front of car that crumples (as long as it doesn't involve the passenger cabin), the better, as this provides a longer distance (and more time) for the car to decelerate. The lower the rate of deceleration, the less force the people in the car will experience. So, if you "tune" the car structure to crumple for the full front end crash called out by NHTSA, it may actually be "too soft" for the IIHS tests, and the deformation could reach the passenger cabin. On the other hand, if the car is tuned for the IIHS tests and crumples the "just right" amount during the offset tests, it may not crumple enough during the more benign full front end test.

I suspect that it's difficult to achieve the "goldilocks" amount of crumpling on all the tests (small offset, offset, and full front end). Toyota decided to prioritize the IIHS testing, perhaps because the IIHS "Top Safety Pick" is a valuable marketing tool.
 

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The IIHS tests are harder to pass because they occur at a higher speed and involve only a portion of the front of the car.

The NHTSA test is a 35 mile per hour impact into a wall. The entire front end structure of the car is involved in dissipating the energy of the crash. This test is analogous to either hitting a concrete wall with zero compliance at 35 miles per hour or hitting another car of similar mass traveling in the opposite direction at the same speed where the front ends of both cars are aligned perfectly (as if both cars were driving in the same lane but in opposite directions). This is not representative of a lot of real world accidents, where the vehicles are not meeting perfectly head-on.

The IIHS tests are a 40 mph impact into an offset barrier. Only 40% of the front of the car impacts the barrier during the offset crash test. The small offset test only impacts 25% of the barrier. These tests are more difficult to pass, as a much smaller portion of the front end crash structure must dissipate the crash energy from a higher speed collision.

During an impact, the car is designed to crumple in a controlled manner. This is a bit of a simplification, but the more length of the front of car that crumples (as long as it doesn't involve the passenger cabin), the better, as this provides a longer distance (and more time) for the car to decelerate. The lower the rate of deceleration, the less force the people in the car will experience. So, if you "tune" the car structure to crumple for the full front end crash called out by NHTSA, it may actually be "too soft" for the IIHS tests, and the deformation could reach the passenger cabin. On the other hand, if the car is tuned for the IIHS tests and crumples the "just right" amount during the offset tests, it may not crumple enough during the more benign full front end test.

I suspect that it's difficult to achieve the "goldilocks" amount of crumpling on all the tests (small offset, offset, and full front end). Toyota decided to prioritize the IIHS testing, perhaps because the IIHS "Top Safety Pick" is a valuable marketing tool.
Excellent explanation! If you don’t teach physics, you missed your calling!
 
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