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car seats) than a facility problem, per se. A more likely facility investment issue is whether
safety-related upgrades are made in low-income or minority areas of a community to the same
extent that they are made elsewhere.
In general terms, transportation projects can directly affect travel safety in the following ways:
· Projects that expand road system capacity and reduce congestion will likely reduce
incidents that might lead to a crash, such as a stalled vehicle blocking the roadway.
· Changes in signalization, turning lanes, and passing restrictions can reduce the number of
potential opportunities for conflict between vehicles.
· Improvements in the condition of a roadway, such as resurfacing to remove potholes,
create a safer driving environment and thereby reduce the number of crashes.
As stressed earlier, however, the principal environmental justice issue related to safety is likely
to pertain to nonusers, those whose activities place them near the roadway. Thus, environmental
justice assessments need to consider changes in pedestrian safety and that of bicyclists or users
of other nonmotorized transportation modes. Pedestrian safety needs to focus on (1) those who
must cross a roadway and thus risk potential conflict with motor vehicles and (2) children whose
play and travel place them in harm's way. For bicyclists, the emphasis should be on road
characteristics that affect their ability to travel safely on the facility.
It is important to note that safety improvements for road or highway users may not correlate with
improvements in safety for these other groups. For example, a wider, faster highway may
improve safety for vehicle travelers but reduce the safety of bicyclists and pedestrians who cross
the facility.
SELECTING AN APPROPRIATE METHOD OF ANALYSIS
It is common practice to estimate the safety changes--in the form of a reduction or increase in
the number of crashes--for any major street or highway project, including new road
construction, reconstruction, capacity expansion, road maintenance, rehabilitation, and
resurfacing, as well as safety and traffic flow improvements. It should not represent a major
additional effort to compare the safety of collector facilities and local streets in areas that are
within the daily activity space of minority populations and low-income populations. Methods for
assessing the safety impacts for users of road projects are quite well established (see
Forkenbrock and Weisbrod 2001, Section 3). Therefore, our focus here is on applying these
methods to determine the extent to which a difference exists between the safety of road users in
low-income or minority districts of the community compared to other areas.
Safety effects also should be estimated in attempting to reduce a specific type of safety problem,
such as conflicts between vehicles and bicycles. Such an analysis may point to the types of
improvements that are best able to reduce the particular safety problem.
Table 6-1 summarizes the methods presented in this chapter.
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Table 6-1.
Summary of methods for analysis of safety effects
Assessment Appropriate Use Data Expertise
Method level uses when needs required
1. Analysis of Screening Assess safety In early stages of design or Low Spreadsheet
national data effects on road for a quick and easy
users and survey of potential safety
pedestrians effects
2. Comparison Screening/ Assess safety In early stages of design Medium Spreadsheet
approach detailed effects on road for more focused analysis
users and of potential safety effects
pedestrians in the same region
3. Regression Screening/ Assess safety Specific improvements are High Statistical
analysis detailed effects of road being considered to analysis
improvements improve road safety
4. Bicycle Screening/ Assess safety There is a significant level Medium/ Spreadsheet
safety index detailed effects on of bicycle traffic in the high
bicyclists affected area
5. Bicycle Screening/ Assess safety There is a significant level Medium Spreadsheet
compatibility detailed effects on of bicycle traffic in the
index bicyclists affected area
6. Pedestrian Screening Assess safety Project will increase the Low Spreadsheet,
street effects on volume and/or speed of Geographic
crossings pedestrians vehicular traffic in high information
pedestrian traffic areas systems (GIS)
7. Pedestrian Detailed Assess safety Project will increase the Medium Spreadsheet
danger index effects on volume and/or speed of
pedestrians vehicular traffic in high
pedestrian traffic areas,
and detailed data on
pedestrian exposure and
injuries is available
8. Barrier effect Detailed Assess safety Project will increase the Medium Spreadsheet
analysis effects on volume and/or speed of
pedestrian and vehicular traffic in areas
non-motorized with high levels of
mobility pedestrian and non-
motorized vehicle crossing
9. User demand Screening Assess road Patterns of road use by Low Survey design,
and use patterns pedestrians and non- spreadsheet
evaluation motorized vehicles are
surveys unknown
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