Can you swap out Gen II front headrests for Gen III?

Greetings all. First time post-er here. My name is Greg and I live in Maryland, USA. I currently don't own a Prius but I'm looking at buying a 2007 Prius Touring soon depending on how things go. I've already read up on this forum about battery module swaps which really puts me at ease to know it can reasonably be done by a DIY'er.

The question I had was regarding the IIHS (Insurance Institute for Highway Safety) scorecard on the headrests/head restraints for the Gen II (2004-2009) cars (I would post a link to their main site but currently can't until I make at least 4 posts). They show that there is a failure due to the time contact between the beginning of a crash to when your head actually reaches the headrest is too long during a rear-end collision. A Gen III version however is able to pass this due to potentially, 1.) the headrest design which is closer to the back of a person's head when installed (backset is 55mm vs 37mm for the Gen II vs Gen III respectively), and 2.) active head restraint (AHR) technology.

I'm not positive currently whether this AHR is within the headrest itself or if it is in the seat but if you could swap out the Gen II for the Gen III headrests mechanically, it would bring the headrest's backset closer than the 55mm, thereby shortening the time between car crash to head hitting the headrest and thus "passing" the IIHS test, making the car safer.

Thoughts? Thanks in advance for your comments, I do appreciate it.

 

As an update which might be making my previous post obsolete, I did find links on Amazon for a head pillow called "GiGi--Driving Comfortable and soft NASA Memory Foam Car Neck Pillow" These push out far enough from the seat to close the backset gap. One of the commenters actually wrote that this could be useful for whiplash. I'll dig into this a little bit more but I may have solved my own problem. The next step will be to just buy the car then, no biggie hah.

 

Thanks for the reply. That's what I was thinking as I was digging more. I found this one that is specifically designed for whiplash prevention. Googling addonheadrest seems to be a good route to go down. Or again if the Gen III's can get swapped, that's another option that I'd like to see if it is viable or not.

 

Replacing the whole seat for at least the driver and potentially the passenger would be a much more difficult and expensive task. While this may be a good option, I was trying to go with a cheaper solution that would satisfy the backset criteria.

I realize that the Gigi version may be too soft (I'll send an email to the manufacturer to see if they have any crash test data for it). But even if it is too soft, it potentially could be useful as a softer shock absorber as a transition to the harder actual headrest below. It would still help out with decelerating the head, the question is by how much.

I'll also be looking more at the other one from the addonheadrest for more test data.

 

I'd appreciate if you'd be able to measure them. For backset measurements, I'm not sure if these are at a particular incline/decline of the seat and where an average passenger's head then sits relative to the head restraint in the typical driving position. I'm just trying to ease my fears of whiplash when from IIHS it showed that it only performed marginally during a dynamic test. The Gen III's did much better for this dynamic test and the 2014's and onwards were when they were able to have an acceptable performance on the small-overlap test (which is a harder test to pass).

 

I had to use some name for this and Greg was taken. Figured it was better than Greg, Fancyman of Cornwood (for you Futurama fans out there). Greg the Engineer has small but realistic ideas of how to make the car safer (ideally).

 

Agreed this could be an issue, but if from IIHS is already on marginal, you might not be able to make it much worse by adding some additional padding with one of the add-ons I wrote about above.

According to their rating criteria at IIHS for the head restraint test, it shows that:

"Injury rates were 15 percent lower for vehicles with seats/head restraints rated good compared with vehicles with seats/head restraints rated poor. Long-term injuries, or those lasting three months or more, were 35 percent lower for vehicles with seats/restraints rated good compared with seats/restraints rated poor."

"IIHS researchers analyzed more than 5,000 insurance claims and determined that drivers with head restraints with good geometric ratings were 24 percent less likely than drivers with poor-rated head restraints to sustain neck injuries in rear-end crashes."

Not sure how much better "marginal" is than "poor".

IIHS for the 2007 Toyota Prius: Seat/head restraint Geometry: Good, Dynamic Rating: Marginal due to time to contact the head restraint after the start of a crash.

 

Would you potentially not get paid out for car insurance for health-related costs in a rear-end collision (normally where you need the head restraint) because you added a modification that was supposed to lessen the acceleration forces on your head, either through the addonhead link or the amazon products?

I'd certainly appreciate that (or perhaps some other members might find that information useful as well).

 

Lastly, I'm not positive if it is the Gen III that they are safer due to the backset being smaller than the Gen II so less acceleration of the head before contact then, or if it is due to the Active Head Restraint system that is built into the Gen III seat in combination with the Gen III headrest/head-restraint itself that makes it "safer"/less prone to whiplast injuries.