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are potentially useful in safety plan development, as a supple- Note that the AASHTO Strategic Highway Safety Plan and all
ment to crash data or when crash data are not available. of the supporting resources (e.g., NCHRP Report 501) intend
This guide addresses the development of safety plans for that multiple issues should be addressed and multiple plans
specific emphasis areas, but does not address the evaluation of developed. The guide deals with addressing one issue at a
the effectiveness of those plans after their implementation. For time, but the procedures will be applied multiple times to
evaluation issues, the reader is referred to NCHRP Report 501 address all issues of interest. As described later, the choice will
(18) and to specific safety evaluation tools such as SafetyAnalyst. most often be based on analysis or crash data which assist the
The goals of this guide are the following. user in determining which of the 22 issues/areas defined by
AASHTO or additional jurisdiction-specific issues are most
· Specify a basic three-stage procedure to be used in develop- critical in his or her jurisdiction.
ing an emphasis area plan: (1) choosing an area, (2) setting a
goal, and (3) choosing among potential strategies within the
Stage 2. Set a Crash, Injury or Death Reduction
given area and targeting their implementation to subpopula-
Goal for That Issue
tions of road users, vehicle types, or roadway locations.
· Define data-related procedures for roadway, road user, and The emphasis-area team will then use a series of factors to
vehicle-based emphasis areas that will assist the user in the define a reduction goal for death and injuries in each of the
third stage choosing among potential treatment strate- emphasis areas chosen. AASHTO has suggested that a
gies and targeting the strategies. "stretch goal" be established for both the overall safety
· Define procedures which can be used with three levels of program composed on a combination of emphasis areas, and
safety data and treatment effectiveness: within a given emphasis area. This "stretch goal" is one that
Known treatment effectiveness combined with linkable is not likely to be met by existing safety efforts, or even a
crash, roadway inventory and traffic data limited expansion of these efforts. The goal will push the
Known treatment effectiveness and crash data only jurisdiction to be innovative in defining new programs and
(e.g., no inventory data) procedures to achieve success. The agency may decide to
Unknown treatment effectiveness and crash data only define both a "stretch goal" and a series of reduced or lesser
· Customize the procedures and data descriptions for differ- goals that can be met either within a given time period or with
ent groups of emphasis areas (e.g., lane departure crashes, innovative, but realistic, efforts.
special road-user populations including older and younger
drivers, pedestrians and bicyclists).
Stage 3. Define the Series of Treatments and the
Target Subpopulation (Drivers, Highway Corridors,
The following text will provide an overview of the proposed
Intersections) for Each Treatment That Will Be
data analysis procedures to be covered in this guide. Descrip-
Required to Meet Your Goal
tions of potential safety data files for use in these and other
procedures will be presented in Section II of the guide. General The goal of this step is to develop a combination of treat-
details of the procedures will be presented in Section III. The ment strategies and targets which will allow the user to meet
procedures will then be customized for specific groups of the established goal. In general, this will require the following
emphasis areas in Sections IVXI. Finally, information on steps.
improving existing databases will be presented in Section XII.
1. Define possible subpopulations (e.g., drivers, miles of spe-
cific highway types, intersection types in specific highway
Introduction to Proposed Procedures
classes) for treatment.
As indicated above, the development of a safety- 2. Specify one or more proposed treatments for each target
improvement plan is a multi-stage process. (For clarity, the subpopulation.
term "stage" will be used to describe the major procedures re- 3. If treatment effectiveness is known, determine if the num-
quired to develop the plan. The term "step" will then be used to ber of targets (e.g., miles/drivers/intersections) that can be
describe individual steps/processes required to conduct a given treated in each subpopulation will lead to reductions that
major stage/procedure. Thus, there are "steps" within "stages.") meet the specified goal. If not, add additional treatments
or new target populations (e.g., local roads if the original
targets were on the state system).
Stage 1. Define/Choose Issue(s)/Emphasis Areas
4. If possible, determine whether the benefits derived from
The safety planning team will first define or choose an issue treating the target subpopulations exceed the costs. (Note
(emphasis area) or set of issues that need to be addressed. that this assurance that the treatment is cost beneficial does
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not have to be a separate step. With processes presented public information campaign onto scheduled enforce-
later in this guide, it can be done during the definition of ment activities).
target subpopulations if "full data" are available and if 6. If cost-effective, implement the treatment(s)!
treatment effectiveness is known. This benefit-cost calcu-
lation will not be possible for treatments without defined Note that all these steps may have to be done interactively
effectiveness levels.) until a final solution is reached. In addition, they may not be
5. If a treatment for a specific subpopulation is not cost- done in the sequence shown here. For example, as noted
effective, consider other possible treatments with higher above, the final definition of target subpopulations may be
crash-reduction potential, consider alternative targets done before the determination of strategies, and may also be
(e.g., local road systems if you are a state DOT), or done concurrently with the determination of B/C ratios,
consider ways to reduce the cost of the treatment imple- depending on the methodology used. The following sections
mentation (e.g., combine roadway safety treatment with will provide more specific guidance concerning this overall
other non-safety work at chosen locations, piggy-back procedure tailored to the different types of emphasis areas.
