A Review of Pedestrian Safety Research in the United States and Abroad
Part 4. Summary and Discussion
This synthesis report reviewed existing pedestrian research, particularly as it relates to pedestrian crash characteristics and the effects of various engineering and roadway safety treatments (much less attention was given to educational and enforcement measures related to pedestrians). Emphasis was placed on pedestrian research conducted in the past 10 years.
In addition to reviewing research published in U.S. literature, this report features a limited number of research studies from other countries, and authors in five other countries were hired to conduct similar summaries of pedestrian research in the United Kingdom, Canada, the Netherlands, Australia, and Sweden. This process resulted in the consideration of non-English articles and reports from those countries, with key results given in the research summary. These summaries are provided as separate attachments to this report and are found at the following Web site: http://www.walkinginfo.org/rd/international.htm
Introduction
Part 1 of this report provides an introduction to the pedestrian safety problem. Guides and model pedestrian programs developed in the U.S. in recent years are also discussed, along with illustrations of some of the major pedestrian crash types and countermeasures.
It is clear that pedestrian safety has emerged in recent years as a topic of growing interest and concern. As far back as the 1920s, pedestrian collisions resulted in about 40 percent of all traffic fatalities, annually reaching more than 15,000 pedestrian deaths in the 1930s.
As motorization advanced, that proportion fell, and pedestrian deaths now annually number approximately 5,000 to 6,000 and represent approximately 12-15 percent of traffic deaths each year. This decline is presumably the product of: increased attention to pedestrian control and safety measures and pedestrian safety education; and a change in exposure factors on trips that formerly would have been made on foot that came to be made in a motor vehicle. Other factors also may play a role. Detailed pedestrian exposure data are not available that illuminate pedestrian trip choices and amount of walking on a nationwide basis.
Pedestrian Crash Experience
Part 2 of this report deals with pedestrian crash characteristics. Research since the 1970s of pedestrian crash databases has given us a better understanding of crash causes and related factors. For example, night conditions greatly increase pedestrian crash risk, and, while pedestrian collisions primarily occur in urban areas, higher speed rural collisions more often result in pedestrian deaths. Fridays and Saturdays are the most common days for pedestrian collisions, perhaps because of increased drinking by pedestrians and motorists and more walking exposure on these days.
We know that children are over-involved in pedestrian collisions per population. This is particularly true for males age 5-9. Older pedestrians (particularly above age 65) are much more likely to be killed as pedestrians, possibly because of their increased frailty. Alcohol consumption by the pedestrian is a factor in 40 percent or more of pedestrian deaths, and is a particular factor for male pedestrians age 25-44.
The most common pedestrian crash types include dart-outs, intersection dash, and turning-vehicle collisions. Pedestrians are cited as being solely at fault 43.2 percent of the time, compared with 34.8 percent solely motorist fault. Of course, the assignment of fault depends to an extent on the judgment and biases of the reporting police officers.
Overview of Pedestrian Crash Countermeasures and Safety Programs
The U.S. is the most motorized nation on earth (motor vehicles per capita), and priorities have skewed in favor of the motorist and against the pedestrian. In recent years, however, some attempts have been made to give more consideration to pedestrians. Sometimes this is addressed directly in terms of increased safety for pedestrians accomplished through a variety of traffic calming and other measures. Sometimes the effort is framed as creating a more pedestrian-friendly walking environment in the interest of an improved quality of life, but increased safety is clearly a benefit.
Traffic professionals have had to proceed with less comprehensive knowledge than is desirable about the effectiveness of some measures. While many evaluation results are reported in the literature, it is not always possible to know with sufficient confidence what works and what does not, particularly under specific traffic and roadway situations, because of difficulties in conducting crash evaluations of pedestrian treatments. Low crash samples and threats of regression to the mean, among other difficulties, confound firm conclusions. Thus, when reviewing dozens of published articles and papers on pedestrian research for this report, efforts were made to summarize the results of the best available information and studies.
Many studies were excluded from this synthesis because of questionable research methods or insufficient sample sizes, or because they did not specifically address the safety effects of pedestrian treatments. While this does not imply that every study mentioned in this report is of the highest possible quality, there is a considerable amount of valuable information on the effectiveness of roadway and other treatments for pedestrians. In addition to pedestrian crash data, numerous studies use pedestrian and motorist behavior, vehicle speeds, conflicts, and other measures when analyzing the effects of different pedestrian treatments.
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| Figure 51. Undivided highways had the highest crash risk for pedestrians. |
Some major findings are:
- There is evidence that substantially improved nighttime lighting can enhance pedestrian safety in certain situations.
At uncontrolled crosswalks (i.e., no stop sign or traffic signal on the approach roadway) on a two-lane road, the presence of a marked crosswalk is
associated with no difference in pedestrian crash rate, compared to an unmarked crosswalk. On multi-lane roads with traffic volumes above 12,000 vehicles per
day, having a marked crosswalk alone, without other substantial improvements, is associated with a higher pedestrian crash rate (after controlling for other
site factors) compared to an unmarked crosswalk. More substantial improvements are recommended to provide for safer pedestrian crossings at many such
pedestrian crossings, such as adding traffic signals with pedestrian signals when warranted, providing raised medians, initiating speed-reducing measures,
and/or others. Providing raised medians on multi-lane roads can substantially reduce pedestrian crash risk and can help pedestrians cross the street. At intersections with traffic signals, adding a WALK/DON'T WALK signal with a standard timing scheme (i.e., motorists move parallel to pedestrians and
may turn right or left on a green light across pedestrians' path) has no significant effect on pedestrian crashes. Providing an exclusive pedestrian interval
(i.e., motorists are stopped in all directions during the same interval each cycle while pedestrians cross in any direction) reduces pedestrian collisions by
half. However, exclusive timing schemes can increase pedestrian and motorist delay and are most appropriate at downtown intersections with a combination of
heavy pedestrian volumes, good pedestrian compliance, and low vehicle volumes. Allowing vehicles to make a RTOR maneuver appears to result in a small but clear safety problem for pedestrians. In fact, 21 percent of motorists
violate NTOR signs if given the opportunity, and 23 percent of RTOR violations result in a conflict with a pedestrian. Countermeasures that have been effective
in reducing pedestrian risks related to RTOR include illuminated NTOR signs, offset stop bars at intersections where RTOR is allowed (i.e., motorists are
more likely to make a full stop often), variations in NTOR signs, and others. Various innovative pedestrian and motorist warning signs have been found to reduce vehicle speeds or conflicts between pedestrians and motorists.
These devices include the "strong yellow green" pedestrian warning sign, YIELD TO PEDESTRIANS WHEN TURNING sign, PEDESTRIANS WATCH FOR TURNING VEHICLES
sign, three-section WALK WITH CARE signal head, a DON'T START display to replace the flashing DON'T WALK display, and others. Curb medians provide a safer environment for pedestrians compared with two-way left-turn lanes (TWLTLs). Undivided highways present the highest crash
risk for pedestrians. Numerous treatments can address the needs of pedestrians with disabilities: textured pavements, audible and vibrating pedestrian signals, larger signs
and pedestrian signals, wheelchair ramps, and others. While formal safety studies are very difficult to conduct on such treatments, certain benefits may
result from such devices, depending on site conditions and pedestrian needs. Careful placement of bus stops can affect pedestrian safety. It is clearly beneficial to put bus stops on the far side of an intersection and at
locations with good sight distance and alignment (e.g., not on steep grades or on horizontal curves). School trip safety can be enhanced by sidewalks and proper signalization, but also by well-trained adult crossing guards and selective police
enforcement. Certain warning signs (e.g., flashing school speed limit signs) and markings (e.g., school crosswalks) are also appropriate and beneficial to
pedestrians in many school zones. Pedestrian safety and mobility are enhanced by sidewalks and walkways. This is a critical component of a pedestrian transportation network in urban
and suburban areas. Rural roads should have shoulders for pedestrian travel. Overpasses and underpasses can substantially improve safety for pedestrians needing to cross freeways or busy arterial streets at certain locations.
However, such facilities must be carefully planned and designed to encourage pedestrians to use the facilities and not continue to cross at street level.
Pedestrians can make themselves more visible by using a flashlight, jogger's vest, dangle tags, and rings (retroreflective material on the head band,
wrist bands, belt, and ankle band). Such measures can increase a pedestrian's visibility distance up to 397 m (1300 ft), compared with about 61 m (200 ft)
for a "base pedestrian" wearing blue jeans and a white t-shirt. Several studies have shown that converting from two-way to one-way streets can substantially reduce pedestrian collisions. However, converting from
two-way to one-way streets may not be solely justified by pedestrian safety considerations. More often, several concerns such as capacity, traffic circulation,
and overall traffic safety are major considerations. One-way streets can greatly simplify the task of crossing a street, particularly if the one-way street
conversion does not result in increased vehicle speeds. While traffic-calming measures are primarily intended for neighborhood streets to reduce vehicle speeds and/or reduce cut-through vehicle traffic,
such measures as street closures, speed humps, chicanes, traffic curbs, diverters, and others are in use in various U.S. cities. While controversial, many
of these measures have been found to be effective in improving safety for pedestrians and/or traffic as a whole based on reductions in crashes, vehicle speeds,
and/or reductions in cut-through traffic on neighborhood streets. Education for pedestrians has been found in a few studies to reduce crashes involving child pedestrians. However, most U.S. educational programs were
found to have received little if any formal evaluations or to have had only limited measurable effects. Enforcement of traffic laws and regulations represents another important element in safe pedestrian activity in a roadway environment. This includes
not only enforcing pedestrian regulations (e.g., jaywalking, crossing against the signal) but also motorist actions related to pedestrians (e.g., speeding,
yielding to pedestrians when turning, drunk driving). While a number of U.S. cities (e.g., Seattle, Milwaukee, San Diego) have had active police enforcement
programs in recent years, no quantitative studies are known that have determined the specific effects of police enforcement on pedestrian crashes and
injuries. Further, such a study would be very difficult to conduct because of the many other contributing crash factors in a city.
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| Figure 52. Textured pavements at crosswalks may help vision-impaired pedestrians to cross streets |
Summary reports of pedestrian research are provided at http://www.walkinginfo.org/rd/international.htm for the United Kingdom, Canada, the Netherlands, Scandinavia, and Australia. While much has been learned from pedestrian research over the past two or three decades, there is still much to discover about measures that might affect safety and mobility for those who choose to walk.
FHWA-RD-03-042
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