Whether the doors can be opened after a frontal crash is an important indicator of structural strength. Jammed doors are an inconvenience at best and can put lives in danger at worst.
NHTSA's 35-mph full frontal crash test program included door operability data in most of its reports, typically listed as "easy", "difficult", or "tools required" in earlier years and "opened without tools" or "tools required" in later years.
"Easy" means that the door opened as normal, "difficult" means that it opened without tools but took extra effort to open, and "tools required/jammed" means that the door could not be opened by hand and required tools such as a crowbar or cutting torch to open.
I then averaged the results, giving a full point to "easy" or "opened without tools", a half-point for "difficult", and no points for "tools required", and gave the model year a "Door Operability Index".
Every model year from 1979-2002, 2004, and 2008 are covered, a total of 889 vehicles. The reason for the omission of some later model years is that the percentage of operable doors approached 100 percent, and the report files for later model years tend to be larger. Cost-benefit wasn't worth it.
When the test program started in 1979, less than half of front doors were operable after the crash; by 2004, virtually all were. Even rear doors frequently jammed in those early years. Although the graph is far from a straight line, with certain years being better or worse than expected, the improvement trend is clear.
In the first round of NHTSA testing (1979-1980) a little less than half of front doors and a little more than half of rear doors were operable. Initially, this percentage dropped; from 1981-1983, just 23% of front doors were operable! By the late 1980s, over half of front doors and a vast majority of rear doors could be opened after the crash.
A very rapid improvement happened in the early 1990s, and for most of the 1990s the openability percentage hovered in the 80s for the front doors; jammed rear doors had become very rare. Jammed doors in any position became extremely rare in the new millennium.
No jammed doors were found on any 2004 vehicles, and only one of 47 2008 models tested had jammed doors (oddly enough, the rear ones)
Next few posts: the raw numbers from this analysis.
NHTSA's 35-mph full frontal crash test program included door operability data in most of its reports, typically listed as "easy", "difficult", or "tools required" in earlier years and "opened without tools" or "tools required" in later years.
"Easy" means that the door opened as normal, "difficult" means that it opened without tools but took extra effort to open, and "tools required/jammed" means that the door could not be opened by hand and required tools such as a crowbar or cutting torch to open.
I then averaged the results, giving a full point to "easy" or "opened without tools", a half-point for "difficult", and no points for "tools required", and gave the model year a "Door Operability Index".
Every model year from 1979-2002, 2004, and 2008 are covered, a total of 889 vehicles. The reason for the omission of some later model years is that the percentage of operable doors approached 100 percent, and the report files for later model years tend to be larger. Cost-benefit wasn't worth it.
When the test program started in 1979, less than half of front doors were operable after the crash; by 2004, virtually all were. Even rear doors frequently jammed in those early years. Although the graph is far from a straight line, with certain years being better or worse than expected, the improvement trend is clear.
In the first round of NHTSA testing (1979-1980) a little less than half of front doors and a little more than half of rear doors were operable. Initially, this percentage dropped; from 1981-1983, just 23% of front doors were operable! By the late 1980s, over half of front doors and a vast majority of rear doors could be opened after the crash.
A very rapid improvement happened in the early 1990s, and for most of the 1990s the openability percentage hovered in the 80s for the front doors; jammed rear doors had become very rare. Jammed doors in any position became extremely rare in the new millennium.
No jammed doors were found on any 2004 vehicles, and only one of 47 2008 models tested had jammed doors (oddly enough, the rear ones)
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