鑻辨枃鍘熸枃
The
antilock
braking
system
anomaly:
a
drinking
driver
problem
David W. Harless , George E. Hoffer
Department
of
Economics,
Virginia
Commonwealth
Uni_ersity,
Box
844000,
Richmond, VA 23284, USA
Received
30
November
2000;
received
in
revised
form
19
February
2001;
accepted 28 February 2001
An
important
anomaly
with
the
incorporation
of
safety
appliances
into
motor
vehicles
is
the
ineffectiveness
鈥?/p>
and
even
perverse
effects
鈥?/p>
of
antilock
braking
systems
(ABS),
particularly
as
measured
by
fatal
crash
involvement.
Analyses
of
insurance
claims
in
the
US
(Highway
Loss
Data
Institute,
1994,
1995)
showed
no
change in claim frequency after a set of GM vehicles adopted antilock brakes in 1992
despite engineering studies showing antilock brakes resulted in much better braking
performance, especially on wet roads. Using the same group of GM vehicles, Farmer
et
al.
(1997)
found
that
adoption
of
ABS
resulted
in
more
1993
鈥?/p>
1995
crashes
resulting
in
the
death
of
an
ABS
vehicle
occupant.
Another
group
of
vehicles
that
adopted antilock brakes as early as 1985 were found to have been involved in both
more
fatal
crashes
resulting
in
the
death
of
an
ABS
vehicle
occupant
and
more
involvements
overall.
These
perverse
effects
were
most
evident
in
single-vehicle
crashes. Updating the earlier paper with 1996
鈥?/p>
1998 data on the same two groups of
vehicles, Farmer (2001) finds that the ABS-equipped vehicles no longer had a worse
fatal accident involvement rate
[16]
.
The
ABS
anomaly
has
sparked
a
large
program
of
research
at
the
National
Highway
Transportation
Safety
Administration,
the
many
components
of
which
are
described by Garrott and Mazzae (1999). Several explanations have been forwarded
for the anomaly. First,
consistent
with
the risk compensation hypothesis, the higher
incidence
of
fatal
crashes
could
be
due
to
increased
speed
and
aggressiveness
by
drivers of ABS equipped vehicles (Evans, 1995; Evans and Gerrish, 1996). Second,
there may be problems with improper operation of ABS-equipped vehicles: the higher
incidence
of
single
vehicle
crashes
could
be
due
to
abrupt
steering
changes
by