The National Academies Press

Currently Skimming:

Pages 6-31

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 6... ... 3 CHAPTER 2. LITERATURE REVIEW A review of completed and ongoing research has been conducted to identify current knowledge or methodologies that may be appropriate for predicting pedestrian safety effects related to roadway geometrics and other factors. Read the entire page →
From page 7... ... 4 Pedestrian Collision Models for Urban Intersections. Another recent paper by Lyon et al. Read the entire page →
From page 8... ... 5 Pedestrian Volume Pedestrian volume, also called pedestrian exposure, has been found by several studies to be one of the most influential factors in predicting pedestrian crashes. Zegeer et al. Read the entire page →
From page 9... ... 6 The above studies used data on average daily traffic (ADT) , which is generally collected on a regular basis for most major roads in developed areas. Read the entire page →
From page 10... ... 7 TABLE 1. Effects on Crashes of Road Narrowing and Curb Extensions at Intersections (6, 14) Read the entire page →
From page 11... ... 8 difference in pedestrian crash rate, compared to an unmarked crosswalk. Further, on multilane roads with traffic volumes above 12,000 vehicles per day, having a marked crosswalk alone (without other substantial improvements) Read the entire page →
From page 12... ... 9 The consensus from these two studies indicates that crosswalk lighting serves to decrease pedestrian crashes. Median Refuge Islands The Project 17-27 interim report (6) Read the entire page →
From page 13... ... 10 Raised Intersections The Project 17-27 interim report (6) mentioned only one study that examined the effect of raised intersections on pedestrian crashes. Read the entire page →
From page 14... ... 11 A 1984 study by Robertson and Carter (22) found pedestrian signal indications can have different effects on pedestrian crashes, depending on the type of intersection. Read the entire page →
From page 15... ... 12 Often, a driver who is stopped prior to turning right focuses on traffic coming from the left in order to identify a gap adequate to permit his right turn. Consequently, the motorist does not see a pedestrian on his right and a conflict occurs when the turn is initiated. Read the entire page →
From page 16... ... 13 EFFECT OF ROADWAY SEGMENT CHARACTERISTICS ON PEDESTRIAN SAFETY Research included in this section of the literature review is focused on the effect of roadway segment characteristics on pedestrian safety. Many studies have used non-crash-based measures of effectiveness, such as: • Changes in pedestrian behavior (e.g., increased use of crosswalks, types of crossing behaviors, etc.) Read the entire page →
From page 17... ... 14 ratio" and controlling for other roadway factors, the likelihood of a site with a sidewalk or wide shoulder (of 4 ft [1.2 m] or wider) Read the entire page →
From page 18... ... 15 long-term trends in crash occurrence. Standard errors have been adjusted by a factor of 3 for each low quality estimate of effect and a factor of 2.2 for each medium low quality estimate of effect. Read the entire page →
From page 19... ... 16 The limited number of crash-based studies on the effect of pedestrian overpasses and underpasses does not provide definitive results. The Tokyo study indicates that overpasses can reduce pedestrian crashes, but it can be assumed that the safety effect is directly related to the level of usage of the overpasses by pedestrians, which can vary widely. Read the entire page →
From page 20... ... 17 The results of this analysis provide strong evidence that having some area of refuge (either a raised median or TWLTL) on an arterial CBD or suburban street provides a considerably safer condition for pedestrians than having an undivided road (i.e., with no refuge for pedestrians in the middle of the street) Read the entire page →
From page 21... ... 18 Other Factors Without Crash-Based Studies No crash-based studies were found for the following roadway segment (midblock) factors: • Pedestrian-activated flashing yellow beacon • Overhead electronic LED signs (animated eyes) Read the entire page →
From page 22... ... 19 Ci = calibration factor for at-grade intersections developed for use for a particular geographical area AMF1i … AMF5i = accident modification factors for intersections Four types of intersections on arterial roadways are considered: • Three-leg intersections with STOP control on the minor-road approach (3ST) • Three-leg signalized intersections (3SG) Read the entire page →
From page 23... ... 20 where: Nrs = predicted number of total roadway segment accidents per year Nbr = predicted number of roadway segment accidents per year excluding vehicle-pedestrian and vehicle-bicycle collisions Nbrbase = predicted number of total roadway segment accidents per year for nominal or base conditions excluding vehicle-pedestrian and vehicle-bicycle collisions Npedr = predicted number of vehicle-pedestrian collisions per year Nbiker = predicted number of vehicle-bicycle collisions per year AMF1r … AMF3r = accident modification factors for roadway segments Cr = calibration factor for roadway segments developed for use for a particular geographical area Five types of roadway segments are considered: • Two-lane undivided arterials (2U) • Three-lane arterials including a center TWLTL (3T) Read the entire page →
From page 24... ... 21 TABLE 8. Pedestrian Safety Adjustment Factors for Roadway Segments in Urban and Suburban Areas (25) Read the entire page →
From page 25... ... 22 found to be more important than total volumes in predicting the number of pedestrian crashes. However, it is also likely that many jurisdictions do not have resources to collect turning volume information on a regular basis. Read the entire page →
From page 26... ... 23 areas, the pedestrian volume between 10:00 a.m. Read the entire page →
From page 27... ... 24 for each segment is then developed using Space Syntax, generally based on the number of street segments accessible within 3 links. Population density and other demographic characteristics, including median household income, age, and race, were then applied to the Space Syntax model. Read the entire page →
From page 28... ... 25 In addition to the two models discussed above, other methods for estimating pedestrian travel have been tried and applied in various settings. These methods include sketch planning techniques that predict pedestrian travel using simple calculations and rules of thumb about travel behavior; development and application of expansion factors to sample pedestrian counts; and developing estimates based on comparisons to similar locations. Read the entire page →
From page 29... ... 26 TABLE 9. Land Use Variables Associated With Pedestrian Crash Risk. Read the entire page →
From page 30... ... 27 density roadway networks were found to have lower pedestrian crash risk. The model included thirteen variables, shown in Table 9. Read the entire page →
From page 31... ... 28 the risk of child pedestrian injury. Von Kries et al. Read the entire page →

From page 6...

... 3 CHAPTER 2. LITERATURE REVIEW A review of completed and ongoing research has been conducted to identify current knowledge or methodologies that may be appropriate for predicting pedestrian safety effects related to roadway geometrics and other factors.