Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 2
SECTION I--SUMMARY
and low-speed designs, with the definition being low-speed roads with speed limits of
40 mph or less (5 mph less than the highest AASHTO design speed) and high-speed roads
with speed limits of 45 mph or greater (5 mph less than the lowest AASHTO design speed).
Grouping of strategies by speed range is done for convenience and focus. Users of this guide
need not be constrained, however, by the definitions and groupings. A user may find that a
strategy discussed in the low-speed guide may have application and value in a nominally
high-speed condition. This is not only acceptable but considered good use of the guide. The
strategies discussed are shown in Exhibit I-1.
General Description of the Problem
Excessive or inappropriate speeds result from two basic problems, both of which involve
human factors considerations. Driver behavior (i.e., consciously choosing a clearly
inappropriate speed) is one aspect of the problem. The second is associated with driver
response to the environment (i.e., inadvertent selection of a speed that is inappropriate or
unsafe, failure to adjust or change speeds, or failure to perceive the speed environment and
as a result incur risk of a collision or conflict). It is both of these types of problems that this
guide seeks to address.
Approximately 42,000 automobile-related fatalities occur each year in the United States, and
historically, nearly one-third of fatal crashes involve speeding, as shown in Exhibit III-1.
In Traffic Safety Facts 2006--Speeding, the National Highway Transportation Safety
Administration (NHTSA) defines a speeding-related crash as a crash in which "the driver
was charged with a speeding-related offense or if an officer indicated that racing, driving too
fast for conditions, or exceeding the posted speed limit was a contributing factor in the
crash" (NHTSA, 2006). This section details characteristics of speeding-related fatalities and
fatal crashes obtained from a review of recent literature and the NHTSA Fatality Analysis
Recording System (FARS) database.
In 2006, there were 42,708 traffic fatalities, 30 percent (13,113) of which involved speeding.
Of these fatalities, 13,543 (32%) occurred as a result of a speeding-related crash. Only 13% of
all speeding-related traffic fatalities occurred on Interstate roadways, while 72% occurred
on non-Interstate roads. Of the crashes on non-Interstate roads, 29% occurred on low-speed
non-Interstate roads (defined for the purpose of this report as roads with a speed limit of
40 mph or less), and 43% occurred on high-speed non-Interstate roads (roads with a speed
limit of 45 mph or more). Roadways with unknown or no statutory speed limits accounted
for 15 percent of speeding-related fatalities. These data are taken from Traffic Safety Facts
2006Speeding (NHTSA, 2006). A further review of 2005 FARS data yields additional insights
into fatal crash characteristics (NHTSA, 2005):
ˇ Approximately 39 percent of speeding-related fatal crashes occurred on horizontal curves.
ˇ Speeding-related fatalities occur primarily in single-vehicle crashes; 70 percent of
speeding-related fatalities on low-speed roads, and 67 percent on high-speed roads
occurred in this manner of collision.
ˇ 38 percent of speeding drivers in a fatal crash were under the age of 25.
ˇ 40 percent of drivers that were speeding in fatal collisions had a blood alcohol content
(BAC) of at least 0.08.
I-2
