Synthesis of Safety for Traffic Operations - Transports Canada

Synthesis of Safety for Traffic Operations March 2003
Although no details are provided in the article, it is mentioned that the sites are matched
on traffic volumes. It is assumed that this means exposure has been accounted for, and a
comparison of crash frequency is appropriate.
Both treatment and control sites exhibited an increase in the number of crashes, with the
increase in the crashes at the treatment site being greater. This is an indication that the
LSD warning sign has provided no safety benefits (a resulting CMF of 1.09). The
number of crashes used in both the treatment and control groups are statistical small and
do not lend themselves to making statistically significant conclusions respecting the
safety impacts of the LSD signs. Therefore, it is not appropriate to conclude that the LSD
signs have been detrimental to safety.
It is worthy to note that the term “sight distance” is engineering terminology and it’s
meaning is not likely understood by many drivers.
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