Skip to main content

Currently Skimming:


Pages 14-23

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 14...
... 14 Safety Performance and Intersection Sight Distance The purpose of this chapter is to provide practitioners information on the anticipated impact on crashes at an intersection from changing the sight distance (e.g., lengthening the distance at an intersection from 400 ft to 750 ft by removing a sight distance obstruction)
From page 15...
... Safety performance and Intersection Sight Distance 15 Practitioner Tips: Detailed Instructions for Using CMFs The following information provides step-by-step guidance on how to use the charts to determine the crash impact from changing the existing ISD to a new proposed ISD. A sample graph (Figure 6)
From page 16...
... 16 Guidance for evaluating the Safety Impacts of Intersection Sight Distance Figure 6. Sample chart.
From page 17...
... Safety performance and Intersection Sight Distance 17 Chart A-2. CMFs for target crashes when posted speed equals 40 mph.
From page 18...
... 18 Guidance for evaluating the Safety Impacts of Intersection Sight Distance Chart A-4. CMFs for target crashes when posted speed equals 50 mph.
From page 19...
... Safety performance and Intersection Sight Distance 19 Chart A-6. CMFs for target crashes when posted speed equals 60 mph.
From page 20...
... 20 Guidance for evaluating the Safety Impacts of Intersection Sight Distance Chart B-2. CMFs for target fatal and injury crashes when posted speed equals 40 mph.
From page 21...
... Safety performance and Intersection Sight Distance 21 Chart B-4. CMFs for target fatal and injury crashes when posted speed equals 50 mph.
From page 22...
... 22 Guidance for evaluating the Safety Impacts of Intersection Sight Distance Analyzing More Than One Approach The crash modification factor for intersection-level target crashes can be calculated using the following equation: ∑ ∑= × CMF CMF T T IT T i i i where: CMFIT = crash modification factor for intersection-level target crashes, CMFTi = crash modification factor for target crashes for approach direction i, and Ti = target crashes for approach direction i. If the intersection has three legs, there will be two approach directions.
From page 23...
... Safety performance and Intersection Sight Distance 23 where: CMF = crash modification factor total intersection crashes, and PT = proportion of total intersection crashes that are target crashes. This equation assumes that only target crashes will be affected by the change to ISD and requires the CMF for intersection-level target crashes and the proportion of total intersection crashes that are target crashes.

Key Terms



This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.