# Do Seatbelts Sometimes Kill?

**URL:** <https://boards.straightdope.com/t/do-seatbelts-sometimes-kill/587739>\
**Category:** Factual Questions\
**Created:** [July 3, 2011, 7:08pm UTC](https://boards.straightdope.com/t/do-seatbelts-sometimes-kill/587739 "2011-07-03T19:08:09Z")\
**Posts on this page:** 2\
**Page:** 5

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**Author:** ![Monty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monty/32/47_2.png) [@Monty](https://boards.straightdope.com/u/Monty)\
**Post date:** [September 3, 2015, 12:29am UTC](https://boards.straightdope.com/t/do-seatbelts-sometimes-kill/587739/81 "2015-09-03T00:29:05Z")

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> [@Sicks\_Ate](#):
>
> Plantaaaaains?

Graaaains!

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**Author:** ![SanibelMan](https://avatars.discourse-cdn.com/v4/letter/s/a88e4f/32.png) [@SanibelMan](https://boards.straightdope.com/u/SanibelMan)\
**Post date:** [September 3, 2015, 1:58am UTC](https://boards.straightdope.com/t/do-seatbelts-sometimes-kill/587739/82 "2015-09-03T01:58:18Z")

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While doing some research on the 1989 Loma Prieta Earthquake, I came across a [detailed report from the California Highway Patrol](https://archive.org/stream/lomaprietaearth1990cali_5#page/n95/mode/2up) about the collapse of the Cypress Street Viaduct. Obviously, the collapse of the structure proved fatal to many drivers and passengers whether they were wearing seat belts or not – 35 on the lower deck and 7 on the upper deck. But one interesting and tragic aspect was the case of a Dodge van, [a vanpool from UC San Francisco to Alameda,](http://community.seattletimes.nwsource.com/archive/?date=19901014&slug=1098256) driving southbound on the upper deck. According to the report (page IV-85, listed as “Vehicle 37” in the report above), the driver and all seven passengers were wearing their seat belts. But only one of the passengers in the rear – where there were no seat belts, only lap belts – survived, and with critical injuries. The report says the van hit the collapsed structure at an estimated speed of 27 mph. But five of the passengers were killed by the internal injuries caused by the force of the crash applied through their lap belt.

The report also summarizes seat belt usage for all drivers and passengers on the structure:

> [@](#):
>
> Seatbelt Usage and Injury Severity
> 
> Approximately 64.5 percent of all involved drivers and passengers were  
> reportedly using their seatbelts when the earthquake struck. The seatbelt use  
> on the southbound upper deck was approximately 77.6 percent and approximately  
> 49.5 percent on the northbound lower deck. The seatbelt usage for  
> approximately 5.8 percent of involved drivers and passengers could not be  
> determined. As the majority of these drivers and passengers were on the  
> northbound lower deck, it is possible that the percentage of occupants using  
> restraint systems on the lower deck was greater than the reported 49.5  
> percent. Approximately 66.7 percent of the involved drivers and passengers on  
> the surface streets immediately adjacent to the Cypress Structure were wearing  
> their seatbelts.
> 
> A comparison of injury severity to seatbelt use for all involved drivers and  
> passengers indicates that restrained occupants were, on average, twice as  
> likely to be uninjured as were their unrestrained counterparts.
> 
> Of particular interest was the comparison of the percentage of fatal injuries  
> suffered by restrained and unrestrained occupants. On average, the percentage  
> of unrestrained occupants who suffered fatal injuries was twice that of  
> restrained occupants.
> 
> The percentage of restrained occupants suffering “other visible” and “severe”  
> injuries was greater than their unrestrained counterparts. However, this  
> anomaly can be contributed to the fact that a larger percentage of restrained  
> occupants survived than did unrestrained occupants, adding to the percentage of  
> restrained occupants suffering other than fatal injuries.
> 
> Not surprisingly, seatbelts save lives. Not only in traffic collisions, but  
> during catastrophic events such as earthquakes.

The moral of the story here, though, isn’t “don’t wear your seat belt” – it’s “passenger vans from the 80s and 90s are unsafe”.

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