Ask the Car People.SM


Sienna - Passenger Safety Issue

9 messages,  Last post on Apr 28, 2011 at 11:49 AM

You are in the Toyota Sienna Forum.

What is this discussion about? Toyota Sienna, Crash Test Ratings, Van

Messages Page 2 of 2

#5 of 9 Sienna Ratings by indyguy5

Mar 01, 2011 (1:42 pm)

I've been in the market for a minivan as well and thought the 2011 Sienna would be a good option for us since it has an AWD version. I was dissapointed when I saw it had a low frontal crash test rating, especially for the front passenger. I contacted several area Toyota dealerships and none of them seemed to know why the rating was so low and pitched "its a top saftey pick". I also contacted IIHS and got a bolierplate response with no real specificts to the vehicle. Personally, without knowing any other facts about the test, buying it would be a known risk. I'm also perplexed why it is a top saftey pick especially considering the Odyssey has 5 star ratings and just as much, if not more, saftey options. This seems very misleading to buyers. Personally, I'm opting for the 2011 Odyssey. From my research, it costs slightly more than the Sienna but saftey is my main concern.

#6 of 9 Re: Sienna Ratings [indyguy5] by pact95

Mar 03, 2011 (5:01 am)

Replying to: indyguy5 (Mar 01, 2011 1:42 pm)
I wanted to provide some information I received from the NHTSA on the crash test of the Sienna, with some comparison to the Honda. Hopefully this helps people with their decisions.
 
The Toyota Sienna received a 2-star rating for the right front passenger while the Honda Odyssey received a 5-star. This rating is based purely on injury readings from the dummies which are converted into a percent change of serious injury to a similarly-sized and positioned occupant in a similar crash. The two right front passengers experienced the following percent chances of injury:
 
                    Sienna Odyssey
HEAD 6.65% 0.15%
NECK 14.16% 7.23%
CHEST 8.33% 0.26%
FEMUR 2.56% 2.47%
  
As you can see, the Sienna’s right front passenger experienced a significantly higher risk of injury to her head, neck, and chest than the passenger in the Odyssey did. While it is essential to examine aspects of the vehicle structure like you have below, the most crucial component in understanding why these vehicles performed differently in the full-width frontal barrier test also requires an examination of their airbags and seat belts, commonly referred to as the “restraint system.” The restraint system in the Odyssey allowed for its right front occupant to manage crash forces much more successfully than the system in the Sienna. The details of how or why one system is more successful at this than another is a question better posed to the individual vehicle manufacturers, as NHTSA is not intimate with the specifics of how each manufacturer designs their systems.
 
I have addressed your specific questions below:
Similarities in the reporting:
· - The cars had same model crash test dummies
Response: Correct.
 
· - Both underwent the same impact speed and obstacle
Response: Correct. It is also of note that the Sienna was 95 kg heavier than the Odyssey was. Because the Sienna was more massive, it required its occupant to manage more crash forces than the Odyssey.
 
· - The rebound of the car off the wall appears to be remarkably similar. All measurement points appear close to 100mm off. I would have to imagine that this is a very small amount difference. Additionally, it would appear that the Honda rebounded further. Would that not indicate more force on the items within the vehicle?
Response: In actually, 100mm is a noticeable difference in front-end crush (the range of total front-end crush for the entire fleet is well under 1000mm, including small cars, large sedans, pickup trucks, etc). The differences between these two were not actually 100mm, and averaged nearly 59mm across the front end.
 
                  Sienna Odyssey Difference
C1 346 393 47
C2 479 490 11
C3 471 536 65
C4 472 541 69
C5 524 512 -12
C6 252 423 171
AVE 424 482.5 58.5
  
Though vehicle acceleration data was lost for the 2011 Sienna, typically the two vehicles do have similar deceleration profiles. I reviewed the rebound footage in both tests and agree with your first observation that they were similar. Overall, the Odyssey experienced more crush and therefore absorbed more energy across its front end. However, as I have indicated above, the vehicles differed slightly with respect to test weight, and examining the front-end structure only gives part of the story when examining how the crash forces are experienced, and subsequently managed, by the occupants inside.
 
· - Vehicle profile measurements appear again to be fairly similar. The measurements seem to indicate the car absorbed roughly the same impact and crumple zones absorbed the impact in a similar manner in measurement.
 
· - The “CRUSH PROFILE” appears to be very similar data as well, supporting the statement in the bullet above. I do see that on the Toyota row “L” totals “C1 to C6” and shows a number that clearly adds the cells above where the Honda in the same cells totals some number that is not equal to the cells above. Hopefully this number is not necessary for a crash test result.
Response: The crush profile is not used in the star rating. Again, as I stated previously, crush and front end response is not the entire story in determining an occupant’s chance of injury. “L” is a measure of the front end width of the vehicle before and after the crash, not the addition of C1 to C6, and is also not necessary for the star rating.
 
· - It appears that the passenger side floorboard data shows the Toyota to me more structurally sound.
Response: Floorboard data could have an effect on foot and lower leg accelerations; however, neither of these are reflected in our star ratings. As an aside, the level of floorpan intrusion at the passenger’s position in both vehicles is very similar and also negligible.
 
Differences in the reporting:
 
· - The occupant summary is confusing to me. It almost seems as though the numbers in some of the table data are calculated completely different between the two tests. This would be page 1-1 in Toyota review and page 2 in Honda review. If the numbers take the same inputs and use the same algorithms, I would expect the numbers to be closer, maybe off by some magnitude. These are off by some magnitude and then compounded by the sign, they seem worlds apart.
Response: What you are seeing in terms of injury readings in each test is indeed accurate. I have converted them to their corresponding percent chance of injury in the chart above so you may see how they differ. In all cases, positive or negative, the larger the number, the higher the injury reading (so, larger is worse). The Sienna’s injury readings were significantly poorer than the Odyssey’s. The sign convention for neck compression, chest displacement and femur readings should be negative since they are compression-related injuries (it is understood that they are negative). The sign is often times implied. We apologize for the confusion.
 
· - Page 2-2 of the report shows no knee airbag installed in the Toyota Sienna yet on page 2-17 shows both airbags exist in table “TEST DUMMY INFORMATION AND CONTACT” and again shows no airbag in table “SUPPLIMENTAL RESTRAINT SYSTEM INFORMATION”. I am confused about whether this vehicle in the test had/didn’t have a knee airbag for the passenger. Since I own one, I suspect it didn’t as mine does n

#7 of 9 Re: Sienna Ratings [pact95] by pact95

Mar 03, 2011 (5:06 am)

Replying to: pact95 (Mar 03, 2011 5:01 am)
I saw that some of my information had been truncated. I wanted to provide the remaining...
 
· - Page 2-2 of the report shows no knee airbag installed in the Toyota Sienna yet on page 2-17 shows both airbags exist in table “TEST DUMMY INFORMATION AND CONTACT” and again shows no airbag in table “SUPPLIMENTAL RESTRAINT SYSTEM INFORMATION”. I am confused about whether this vehicle in the test had/didn’t have a knee airbag for the passenger. Since I own one, I suspect it didn’t as mine does not. There appears to be a flaw in your report though.
Response: The passenger dummy did not have a knee airbag, but the driver did. I will alert the proper personnel of the error in the report.
 
· - Was trying to compare the seat angle and position. In both reports, it is hard to grasp the angle of the passenger seat and the position within the car. I see reference to detents, what are these? Can I get further clarification on this data?
Response: The seat angle and the subsequent position of the occupant with respect to the airbag dependents largely on the seat’s range of adjustment as designed by its manufacturer. “Detents” refer to the positioning and adjustment “notches” each seat is designed with by its manufacturer. Our program uses the seating procedure from FMVSS No. 208 to position the seats and the dummies. That procedure can be found here:
http://www.nhtsa.gov/Vehicle+Safety/Test+Procedures
 
You’ll specifically want to examine the procedure for a Hybrid III 50th male in the driver’s seat and a Hybrid III 5th female in the right front passenger’s seat.
 
Thanks to all. Hopefully this helps some people gain clarity.
 

#8 of 9 Re: Sienna Ratings [pact95] by indyguy5

Mar 03, 2011 (6:54 am)

Replying to: pact95 (Mar 03, 2011 5:06 am)
Good information, breaks it down to more usable percentages. We bought the Odyssey yesterday. It think it was the right choice for us. We also considered the Quest since it seems very competative but didn't have ratings out for it.

#9 of 9 Re: Sienna - Passenger Safety Issue [siennathinking] by siennathinking

Apr 28, 2011 (11:49 am)

Replying to: siennathinking (Feb 26, 2011 8:57 pm)
Interesting... it appears that the NHTSA has just lowered the 2011 Sienna's overall rating from 5 to now 4 stars. Seems like a fairer rating given the very low passenger safety score.
 
http://www.safercar.gov/Vehicle+Shoppers/5-Star+Safety+Ratings/2011-Newer+Vehicl- es/Vehicle-Detail?vehicleId=461

Messages Page 2 of 2

To POST a message, please Sign In.

Advertisement

Browse by Category

Browse by Vehicle
   View All Vehicles

Browse by Board
Browse by Topic
View All Topics

Edmunds Community

Advertisement