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42
SECTION V
Roadway Junctions
Planning Programs Related perspectives, and the perspective chosen determines the
to Reducing Crashes at Signalized choice and targeting of treatments. Some states chose to try
and Unsignalized Intersections to expand their current "high-crash location (HCL)" pro-
gram to include more locations to meet their overall goal.
This section of the guide provides the details of the four Others chose to orient their planning methods to the identi-
levels of treatment choice and targeting procedures described fication and treatment of "systems" of intersections, not just
above in the Stage 3 discussion in Section III, but it is oriented those locations that fell under the HCL program. Indeed,
to those issues/emphasis areas that are specifically related to at- guidance provided in each of the guides, in companion train-
grade intersections angle crashes, turning crashes, sideswipe ing courses, and in the FHWA Sample Plan for intersections
crashes, rear-end crashes, head-on crashes and run-off-road (25) is that system-based programs will need to be included.
crashes. In most instances, a given procedure will follow the If the jurisdiction is really attempting to reach a goal which
same basic steps, regardless of the crash type being addressed. represents a significant change from the current situation a
Where the procedure differs between crash types, this will stretch goal it is very unlikely that expansion of the HCL
be noted. In addition, the data needed for the different program will suffice. While such an expansion is clearly a
intersection-oriented crash types will differ and will be spec- component of a stretch-goal plan, large-scale treatment of
ified. The user is strongly urged to carefully review the ma- systems and corridors will also likely be necessary.
terial in each of the pertinent guides before beginning this Indeed, a jurisdiction can use the following procedure to
planning process. These intersection-oriented guides are determine approximately how much the existing HCL
found within NCHRP Report 500: Guidance for Implemen- program will have to be expanded, which will provide some
tation of the AASHTO Strategic Highway Safety Plan. The guidance on whether system programs should also be
specific volumes pertinent to this section are: considered.
· Volume 5: A Guide for Addressing Unsignalized Intersection 1. Examine the most recent listing of HCL projects that were
Collisions (5) chosen for treatment in your jurisdiction and identify
· Volume 12: A Guide for Reducing Collisions at Signalized In- those that were related to intersection crashes.
tersections (12) 2. Add the numbers of before-treatment crashes, injuries,
and fatalities from each intersection and divide by the
A link to these downloadable guides can be found at http:// number of years of before data to produce a total number
safety.transportation.org/guides.aspx. of potentially treatable intersection crashes and crash
injuries per year.
3. Multiply these totals by 20 percent to get the number of
Possible Program Types Spot versus
intersection crashes, injuries and fatalities that are
System Programs
expected to be reduced per year by your current program.
Before moving to the specific treatment choice/targeting (This assumes an average Crash Reduction Factor of
procedures for these emphasis areas, it is noted that states 20 percent for all intersection strategies. This is probably
who were early participants in the AASHTO safety planning too high, but in the ballpark of reality, and good enough
process for intersection programs started from two different for this exercise.)
