House Concurrent Resolution No. 294, S.D. 1, adopted by the Legislature in the 2005
Regular Session, requested the Bureau to conduct a review of existing studies and statistics on
the causal relationship between wireless telephone use while operating a motor vehicle and
increased motor vehicle-related accidents.
The Bureau reports that studies have found the following:
- The studies find that cellular telephone use while operating a motor vehicle is a
- The studies generally do not prove or disprove that cellular telephone use while
operating a motor vehicle is a cause of motor vehicle collisions. Instead, the
studies generally find that a statistical association, not necessarily a causal
relation, exists between cellular telephone use while operating a motor vehicle
and motor vehicle collisions.
- The studies do not address whether cellular telephone use while operating a motor
vehicle is the most prevalent cause of motor vehicle collisions among collisions
that are caused by a distraction-inducing action. Instead, the studies address
associations, rather than causal relations, between various potential distractions
and motor vehicle collisions. However, no definitive answer has yet emerged as
to which driver distraction is associated with the greatest risk of crash
- Last, the studies find that a hands-free cellular telephone is not much safer than a
hand-held cellular telephone. Both tend to be equally distracting. Moreover, the
type of phone does not affect the statistical association between phone use and the
risk of a crash.
II. Frequently Asked Questions
- Is causation difficult to prove?
Answer: Yes. The gold standard for proving causation is the randomized
experiment, in which a large number of people are randomly selected
and divided into two groups. In this instance, one group would be
required to use cellular telephones while driving. The other group
would be prohibited from using cellular phones while driving. The
task for the experimenters would then be to wait and see which group
is involved in more motor vehicle collisions over a period of time.
Such a study, it is noted, would be very difficult to perform and
- How is an association different from causation?
Answer: Association means that two or more variables are related in some
fashion. In contrast, causation means that two or more variables are
causally linked. An association may be circumstantial evidence for
causation, it does not prove causation.
The following are examples of a causal relation between an event A
and an event B, in which event A causes event B (taken from the
article on "Causality" from Wikipedia, the free encyclopedia, at
In contrast, the following are examples of an association between an
event A and an event B (taken from the articles on "Causality", "Joint
effect", and "Wrong direction", in Wikipedia, the free encyclopedia, at
http://en.wikipedia.org, and from Burns, W.C., Spurious Correlations,
- A cue ball colliding with the eight ball causes the eight ball to roll
into the pocket.
- The presence of heat causes water to boil.
- The moon's gravity causes the Earth's tides.
- A good blow to the arm causes a bruise.
- My pushing of the accelerator causes the car to go faster.
- Good health was associated with bodily lice infestation, during the
Middle Ages. Thus, people of that time incorrectly inferred that
the departure of bodily lice caused sickness. The reverse turned out
to be the truth. The rise in bodily temperature during a sickness
caused the lice to leave.
- The shoe size of a child is associated with the child's reading skills.
Does reading practice cause the feet to grow? Or does growing
feet stimulate the desire to read? Neither is correct. With age, a
child's reading skills naturally improve and the child's feet