Guidance to Improve Pedestrian and Bicyclist Safety at Intersections (2020) / Chapter Skim
Currently Skimming:
Pages 16-34
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 16... ...
16 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Chapter 2: Identify and Collect the Data for Analysis When the process has been framed and the scope is clear, it's time to gather the data needed to conduct the analysis. Making safety decisions without sufficient -- or appropriate -- data can lead to poor use of limited safety funds, or even counterproductive investments, such as measures that actually decrease safety for certain modes.
|
From page 17... ...
17 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Table 2. Minimum Recommended and Ideal Data Types Data Types Purpose Minimum Recommended Ideal Crash Data Primary Data for Reactive and Proactive Approaches The most common and accepted measure of traffic safety at an intersection is police-reported crashes. Police-reported crashes from state database, and/or police reports themselves.
|
From page 18... ...
18 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Data Types Purpose Minimum Recommended Ideal Infrastructure: Geometric Design Primary Data for Proactive Approach Knowing what type of infrastructure currently exists at each intersection can help predict the number of expected crashes at that intersection type. It also helps to build models of which types of infrastructure are most successful in reducing crashes.
|
From page 19... ...
19 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Data Types Purpose Minimum Recommended Ideal Speed Motor vehicle speed is known to contribute to crash severity and likelihood of survival for bicyclists and pedestrians. Speed is also a known factor that influences motorist yielding rates.
|
From page 20... ...
20 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Another option is to take a more systemic, forwardlooking approach to assess and address safety problems associated with the known risk factors present at an intersection even before crashes occur (discussed further in Chapter 3)
|
From page 21... ...
21 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS pedestrian was crossing the intersection within a crosswalk and the motorist was making a left turn from a path parallel to the pedestrian's path, the crash type would be recorded as "motorist left turn -- parallel paths" (see Figure 10)
|
From page 22... ...
22 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS more dangerous than expected based on the traffic conditions. Of course, a high number of crashes is a legitimate reason to focus attention on an intersection for improving safety, but understanding the number of expected crashes, given current conditions, may help guide prioritization to locations with unexpectedly high crashes so that limited safety funds can best be directed to problem locations.
|
From page 23... ...
23 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS or other significant roadway or operations changes were installed or implemented, to avoid falsely correlating them with the crashes they were intended to address. Documenting and accounting for when infrastructure or operational changes were made is an important step to understanding their impact on safety.
|
From page 24... ...
24 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS 2.2.5 Data on Perceived Comfort and Safety While much less common than crash or infrastructure data, data on user perceptions of comfort, safety, or both are important to consider when selecting countermeasures. Research has clearly demonstrated a general preference for more separated bicycle facilities (Sanders 2016; Winters et al.
|
From page 25... ...
25 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS 2.3.2 Conflicts and Avoidance Maneuvers Another way to measure safety is to perform a conflict study to count the number of "near collisions," called conflicts or avoidance maneuvers. Conflict studies can be conducted in the field through manual observation, by manual video observation, or through automated video image processing techniques, some of which are available using open source software (Saunier 2016)
|
From page 26... ...
26 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS installing passive pedestrian detection. Other types of behaviors that are observable include motorists yielding to pedestrians, stopping position/location of motorists, pedestrians crossing against intersection traffic control, and distance between bicyclists and passing vehicles.
|
From page 27... ...
27 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS 2.4 Working with Imperfect Data Using data to make safety decisions is important; however, it is equally important to make sure that the data are of good quality. Just as making decisions based on anecdotal evidence or a single personal experience can lead to poor safety investments, the data that drive a decision need to be reliable and accurate.
|
From page 28... ...
28 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS 2.5 Case Example This section expands on the information presented in Section 2.1.1 and provides a case study of the top crash types and contributing factors using crash data from national, state, and local sources to prioritize safety improvements. The crash types identified here are used to illustrate the countermeasure selection process in Chapters 4, 5, and 6.
|
From page 29... ...
29 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Table 9. Top Pedestrian and Bicyclist Fatal and Severe Intersection Crash Types in North Carolina Top 5 Pedestrian Fatal, Disabling, Evident Injury Intersection Crash Types in North Carolina (NCDOT 2008–2014)
|
From page 30... ...
30 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Motorist Failed to Yield to Pedestrian Motorist failing to yield to pedestrian (Figure 13) , again, does not imply fault but implies that the motor vehicle apparently did not have right-of-way and struck a crossing pedestrian.
|
From page 31... ...
31 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Pedestrian Dash In the pedestrian dash (Figure 14) crash type, the pedestrian crossed into the roadway and was struck by a vehicle, and there is no mention in the crash report that the motorist's view of the pedestrian was obstructed.
|
From page 32... ...
32 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Bicyclist Ride Through– Signalized Intersection This top crash type (Figure 16) in FARS also appears in the top five of the other datasets.
|
From page 33... ...
33 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Bicyclist Ride Out– Sign-Controlled Intersection This crash type (Figure 18) may occur due to similar reasons as the bicyclist ride through–sign-controlled intersection type above.
|
From page 34... ...
34 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Motorist Right Turn– Same Direction This crash type (Figure 21) is commonly called the "right hook" crash.
|
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.