Explanation of erroneous
statements about SMAC and CRASH
additional information on
CRASH and other accident reconstruction and simulation
programs please see the
www.mchenrysoftware.com and the
many technical papers on the website
Over the years, several papers have taken
cheap shots at
CRASH, some funded by automobile manufacturers, and some as
thinly veiled sales pitches for competing software or services. This page
will contain a list of some of the more onerous papers and our responses to the
- In February 1987 at the SAE CRASH3
workshop, a speaker stated that they had found a bug/error in the
CRASH3 program Trajectory Analysis procedure related to the friction
zones. I quickly rose and corrected/educated the speaker that they were
wrong that this was NOT an error/bug! The Trajectory solution procedure
CRASH uses logic and code from
SMAC and in SMAC the line defining the friction zones has a built in 'mirror
image' for simplification of logic.
October 1987 at a CRASH damage analysis coefficient protocol subgroup committee
meeting at SAE a company annouced that they had quickly created a
commercial 'crush coefficient database' product.
- Starting in the 1980s a lot of 'experts' in litigation matters were
misrepresenting the accuracy of CRASH and SMAC, and some were testifying
and publishing that CRASH was more accurate than SMAC? (for example see
the post below about a 2003 book) And that CRASH was a highly accurate
program! We contacted
NHTSA and asked that they send a clarification of the status of SMAC
- In a Jan 30, 1990 letter
Frank Richardson, NHTSA, Chief Field Operations for NASS
responded to our request for clarification.
- Which includes:
- "NASS is a program to collect data on a large sample of
highway crashes ...
- "The PC version of CRASH that we use... We know it has
its limitations (see carl Nash's SAE Paper 870040, CRASH3:
Current Status, 1987 and our August 1989 response to GH Docket
86-06) but it is simple, inexpensive and well suited to the
experience and education level of people we can afford to have
collecting NASS data."
- "We have always recognized that the SMAC computer
program, which was developed for NHTSA in 1972, is more
sophisticated and more accurate than the CRASH3 we are using but
the relative expense and application complexity make it
unsuitable for our purposes"
- Also note due to the overwhelming requests from litigation
attorneys about CRASH,
NHTSA went about with a 'Reformulation
of CRASH' and also created
WinSMASH which is only available for NHTSA NASS teams (so no public
distribution) to avoid further time consuming litigation related
inquiries about CRASH.
- For the 1997 SAE congress we published 4 papers and dealt with 8
reviewers as a part of the peer review process. It was a pleasure to
work with 7 of the 8 reviewers and we thank them for taking the time and
effort to review and provide constructive comments on our papers. One of
the 8 reviewers made the review process an unreasonable and offensive
SMAC or comments to
This page may be periodically updated. At some point we may add references.
Our responses on this page have been presented before. See our
1997 SAE papers for a
starting point. Please send any questions of comments
additional information, please see our website and the many technical papers
referenced on the website |