Crash dynamics of a high speed rear impact

mrosehughes · Nov 30, 2012

Hi all,

A FB friend of mine posted a question (not to me; in a parenting forum, but I would like to answer her if I can) about the dynamics of high speed rear impacts and RFing car seats. Basically she said she's not questioning the safety of RFing, but knows that that safety is due, in a large part, to frontal impacts making up a larger percentage of crashes and would like to know more about RFing vs FFing for rear impacts since 1) people tailgate at high speeds in her area and 2) her DS's seat is in the third row and close to the rear windshield of her small minivan.

I was thinking of suggesting she try to get a seat that allows RF tethering or has a rebound bar given her specific case, but she's a physicist (and I'm a physical scientist) so it'd be great if I could point her to videos or studies that show more specifics.

Brianna · Nov 30, 2012

Post #211 here has a link to a blog written about a crash involving 3 RF'ers rear ended by a semi.

I don't think there's much actual data on it though, if there is any.

bree · Nov 30, 2012

mrosehughes said:
Hi all,

A FB friend of mine posted a question (not to me; in a parenting forum, but I would like to answer her if I can) about the dynamics of high speed rear impacts and RFing car seats. Basically she said she's not questioning the safety of RFing, but knows that that safety is due, in a large part, to frontal impacts making up a larger percentage of crashes and would like to know more about RFing vs FFing for rear impacts since 1) people tailgate at high speeds in her area and 2) her DS's seat is in the third row and close to the rear windshield of her small minivan.

I was thinking of suggesting she try to get a seat that allows RF tethering or has a rebound bar given her specific case, but she's a physicist (and I'm a physical scientist) so it'd be great if I could point her to videos or studies that show more specifics.

You could direct her to the study performed on children 0-23 months: http://fcs.tamu.edu/safety/passenger_safety/certified-tech/rear-facing2.pdf One of the stats that's frequently quoted from the study is that children 12-23 months are 5 times safer RF than FF. Table 3 shows where that number comes from (5.32 is the exact figure), and the heading for that column says "All crashes (including rear)"

Maybe it would give her some peace of mind to know that while she's aware that RF is important for frontal crashes, rear crashes were included in the data.

Pixels · Nov 30, 2012

Rear crashes are statistically rare and generally at low speeds, making up only 4% of serious crashes. Every rear impact has two crashes: the front vehicle experiences a rear impact, and the back vehicle experiences a frontal impact. Also, because both vehicles are moving the same direction, the difference in speed (delta V) is much lower.

It is true that rear facing in a rear impact is more dangerous than forward facing in a rear impact. But because rear impacts are much less common and much less severe in general, when you look at all crash types together, rear facing is still much, much safer overall.

LISmama810 · Nov 30, 2012

Posts 11 and 17 of this thread provide some food for thought: http://www.car-seat.org/showthread.php?t=231248

scariestone · Nov 30, 2012

http://myangelsaliandpeanut.tripod.com/id5.html Since she's a scientist she may completely dismiss anecdotal evidence but I found the above very compelling.

bnsnyde · Nov 30, 2012

I have a 3-year-old RF in the back of our van. It's the only space open and his head is actually toward the center of the van, more so than if he were FF. So in this case the RF has that benefit.

But I would not want to get slammed at high speed from behind, especially with an infant rear-facer. I know statistics are on my side, but things happen. Too bad a seat can't be perfectly ideal for every single type of crash.

mrosehughes · Nov 30, 2012

Thank you all! That helped me a lot by clarifying what I know about the statistics, crash dynamics, and existing anecdotal evidence. And I think it helped her, as well

Crash dynamics of a high speed rear impact

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