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Publication Number:  FHWA-HRT-15-043    Date:  June 2015
Publication Number: FHWA-HRT-15-043
Date: June 2015

 

Investigating Improvements to Pedestrian Crossings With An Emphasis on The Rectangular Rapid-Flashing Beacon

CHAPTER 7. SUMMARY/CONCLUSIONS, DISCUSSION, AND FUTURE RESEARCH NEEDS

OVERVIEW

The goal of this research effort was to improve pedestrian safety at urban and suburban crossing locations by identifying and evaluating low- to medium-cost pedestrian treatments. The treatments were to have the potential to reduce pedestrian crashes at both midblock and intersection locations. While several treatments were considered during early efforts of this project, later tasks focused on the RRFB. The RRFB has received extensive national attention because of high yielding rates observed at several installations. Several studies have found increased driver yielding after installing this device as summarized in table 181. The findings from this FHWA study are also provided in table 181.

SUMMARY OF PHASE I FINDINGS

Findings From Literature Review

Efforts in the initial phase of this project included a comprehensive literature review of pedestrian treatments being used at unsignalized intersections. The appendix to this report contains the entirety of the literature review of these treatments. Certain parts of the literature review were updated or additional literature reviews were conducted as needed to support work done in later tasks in this project.

Review of Pedestrian Crash Data

A review of pedestrian crash datasets was conducted to document the characteristics, circumstances, and contributing factors for crashes at midblock pedestrian crossings and to assess the suitability of these databases for any safety evaluations to be conducted in the research. The following datasets were reviewed:

  • NHTSA FARS.

  • NHTSA GES.

  • FHWA HSIS—included a review of data from the States of California, Minnesota, North Carolina, Ohio, Texas, and Washington.

FARS crash data were reviewed for the years 2005 through 2009, inclusive. During this period, 22,892 pedestrian fatalities occurred in the United States, and 73.0 percent of the pedestrian fatalities occurred at midblock locations. The following statistics apply to the pedestrian fatalities that occurred at midblock locations:

  • 1.3 percent occurred at marked midblock crosswalks.

  • 30.7 percent occurred not in, but near, a marked midblock crosswalk.

  • 68.0 percent occurred at locations that were not near marked midblock crosswalks.

Table 181. Overview of driver yielding results from several RRFB studies.

Study
Number of sites
Driver yieldinga
Unique characteristics of study
2010 FHWA(3) 22 (most in St.Petersburg, FL) 72 to 96 percent (stagedb) Original study that included data for multiple years
2009 FHWA(4) 2 (Miami, FL) 55 to 60 percent day (staged) 66 to 70 percent night (staged) Day and night
2009 Florida(5) 1 (St. Petersburg, FL) 35 percent overall 54 percent activatedc Trail crossing
2011 Texas(6) 1 (Garland, TX) 80 percent (staged) School, overhead
2011 Oregon(7) 3 (Bend, OR) 74 to 83 percent (staged) Two sites had 45 mi/h posted speed limit
2013 California(8) 2 (Santa Monica, CA) See table 182 Two sites where the RRFB and CRFB were alternately used. Data available for a third observation period where back plates were changed
2013 Calgary(9) 6 (Calgary, AB) 98 percent (staged) Before installing RRFB, the yielding was 83percent—type of before treatment not provided
2014 Michigan(10) 1 (South Lyon Township, MI) 69 percent (staged) Comparison with no signs (20 percent), gateway in-street signs (80 percent), combination of gateway and RRFB (85percent)
2014 Texas(11,12) 22 (most in Garland, TX) 34 to 92 percent (staged) Significant variables: city, posted speed limit, crossing distance, one/two way

2014
FHWA
(this study)

12 daytime and 4nighttime (Austin and College Station, TX; Flagstaff, AZ, Milwaukee, WI)

Daytime (staged): RRFB: 22 to 98 percent CRFB: 36 to 95 percent Study compared yielding with beacons with circular and rectangular shapes
Nighttime (staged): RRFB: 53 to 95 percent CRFB: 52 to 89 percent Data were collected at night.

aRange provided shows the average driver yielding for the sites included in the study as reported by the authors. See study reference for details regarding study methodology and whether the findings are significant.
bStaged pedestrian was used to collect the data.
cFindings reported for when the device was activated (i.e., pedestrian pushed the pushbutton).

Table 182. Findings for 2013 Santa Monica, CA study.(8)

Shape
Light
Range when activateda,b (percent)
Range when not activateda (percent)
RRFB
Day
80–85
58–73
CRFB
Day
63–92
57–83
RRFB
Night
80–95
35–60
CRFB
Night
65–90
35–80
RRFB
Dusk
80–85
65–85
CRFB
Dusk
55–100
20–75

aStaged pedestrian was used to collect the data.
bFindings reported for when the device was activated (i.e., pedestrian pushed the pushbutton).

In a review of a nationwide sample of crash data for all crash severity levels from GES, the database includes 10,079 crashes involving a pedestrian from 2005 to 2009, inclusive. Nearly half of the pedestrian crashes occurred at midblock locations. However, only 2.5 percent of the midblock pedestrian crashes were explicitly identified as midblock crossing crashes.

HSIS data for California include crash data only for the State highway system, consisting of approximately 15,520 mi of highways. Data analyzed for this report included the years from 2006 to 2008, inclusive. During the study period, 3,944 pedestrian crashes occurred on the California State highway system. Nearly 70 percent of the pedestrian crashes occurred at midblock locations. Only 2.6 percent of the midblock crashes were classified as occurring at midblock crosswalks.

HSIS data for Minnesota crash data include nearly all crashes statewide; including both State-maintained and local-agency-maintained road systems. Data analyzed for this report included the years 2003 to 2007, inclusive. During the study period, 8,271 pedestrian crashes occurred in Minnesota. Approximately 29 percent of the pedestrian crashes occurred at midblock locations. Only 3.0 percent of the midblock crashes were classified as occurring at midblock crosswalks.

HSIS data for North Carolina include crash data for approximately 62,000 mi of the 77,000mi of roadway on the State-maintained highway system. Data analyzed for this report included the years from 2005 to 2008, inclusive. During the study period, 3,847 pedestrian crashes occurred on the North Carolina State highway system. Nearly 85 percent of these pedestrian crashes occurred at midblock locations. Only 2.7 percent of the midblock crashes were classified as occurring at midblock crosswalks.

HSIS data for Ohio include crash data only for the State highway system, consisting of approximately 19,500 mi of highways. Data analyzed for this report included the years from 2005 to 2008, inclusive. During the study period, 4,127 pedestrian crashes occurred on the Ohio State highway system. Approximately 45 percent of these pedestrian crashes occurred at midblock locations. Only 1.2 percent of the midblock crashes were classified as occurring at midblock crosswalks.

Data for Texas include crash data for both on and off the State highway system. Data analyzed for this report included the years 2003 to 2009, inclusive. During the study period, 3,134,365crashes were included in the Texas crash database. Of these, 39,993 (1.3 percent) were pedestrian crashes. Nearly 50 percent of the pedestrian crashes occurred at midblock locations. Only 136 crashes (0.7 percent of the midblock crashes) were classified as occurring at midblock crosswalks.

HSIS data for Washington include crash data only for the State highway system, consisting of approximately 7,193 mi of highways. Data analyzed for this report included the years from 2005 to 2008, inclusive. During the study period, 1,573 pedestrian crashes occurred on the Washington State highway system. Nearly 40 percent of these pedestrian crashes occurred at midblock locations. Only 5.0 percent of the midblock crashes were classified as occurring at midblock crosswalks.

Local Field Observations

The research team made observations at selected midblock pedestrian crossings with a range of traffic control treatments. Ten midblock pedestrian crossings in 5 States were observed, including sites in 8 different cities. These observations were intended as a source of ideas about how particular crossing types could potentially be evaluated later in the study. The crossings observed were not selected as candidates for evaluation; indeed, many of the observed locations had already been treated in particular ways. The observation periods were typically brief (15 to 30 min), and insights and assessments gained from these observations, by intention, should be regarded as anecdotal rather than definitive.

The limited field observations indicated that the inclusion of flashing lights on pedestrian crosswalk signs rather than just in the pavement surface appeared to substantially increase driver compliance with the law requiring yielding to pedestrians.

Selection of Studies for Phase II

The research team used the information gathered during the literature review and the crash evaluation and combined it with information provided by members of the Technical Advisory Panel to generate a list of five proposed crossing countermeasures that could be evaluated in phase II of this FHWA project. The final selection of the phase II studies was made by the panel and representatives of FHWA during a face-to-face panel meeting and a later conference call. Refinements were made to the study plans during follow-on telephone calls with the panel and FHWA. The following two phase II studies were selected:

  • Closed-course study with the following goal: identify the impacts of beacon shape, size, and placement on object detection in a closed-course setting.

  • Open-road study with the following goal: identify driver yielding behavior to installed assemblies identified at the conclusion of the closed-course study.

SUMMARY AND CONCLUSIONS FROM CLOSED-COURSE STUDY

Traffic control options for a pedestrian crossing include numerous combinations of signs and flashing beacons/LEDs. To investigate the influence of beacon characteristics on drivers, participants drove on a closed course at the Texas A&M Riverside campus. During each lap, the participants viewed 8 study assemblies, 9 distractor signs, and up to 11 objects. The types of objects were a pedestrian (dressed in blue scrubs), a trash can, and a small gray box. The study assemblies included the following:

  • Two circular 12-inch beacons located above the sign (named C-A12 in the study).

  • Two circular 12-inch beacons located below the sign (C-B12).

  • Two circular 8-inch beacons located below the sign (C-B8).

  • One circular 12-inch beacon located above the sign and one circular 12-inch beacon located below the sign (C-V12).

  • Two rectangular beacons located above the sign (R-A).

  • Two rectangular beacons located below the sign (R-B), the format currently being used for the RRFB device.

  • Sign with LEDs embedded into the border (LED).

  • Diamond-shaped sign with no beacons or LEDs (WO-B).

Specific research objectives for this closed-course study were the following:

  • Determine whether the shape, size, and placement of flashing beacon/LEDs affect the following:

    • Sign legibility and symbol identification distances.
    • Object detection.

  • Determine driver ratings of disability glare for 8-inch circular beacons and LED-embedded signs using a rapid flash pattern.

  • Identify up to two assemblies for field evaluation to be conducted following the conclusion of the closed-course tasks.

Driving Portion

Each participant drove the course twice with a pause between laps for the field crew to switch the signs and objects for the second lap. After the participants completed the driving portion of the study, they were directed to the discomfort glare portion of the study. The tasks for the participants while driving the route were to indicate when they could first do the following:

  • See warning lights.

  • See road signs.

  • Read the words or identify the symbol on the road signs.

  • See objects.

As soon as the driver said “lights,” “sign,” “object,” or read the words/numbers/symbol on a road sign, the experimenter pressed a key on the laptop computer, which placed a mark in the file to indicate detection. Each sign on the course had two to three marks in the data file: one for detection distance of the sign, one for legibility distance, and (if lights were included on the sign or sign assembly) one for detection distance of the lights. Each object had one mark in the file.

Discomfort Glare Portion

At the beginning of the discomfort glare study, researchers asked the participants to park 250 ft away from sign 1. After the participant parked the vehicle, researchers turned on the beacon and asked the participant to indicate whether the brightness of the light was comfortable, irritating, or unbearable, which were defined as follows:

  • Comfortable—when the glare is not annoying and the device is easy to look at.

  • Irritating—when the glare is uncomfortable; however, the participant is still able to look at it without the urge to look away.

  • Unbearable—when the glare is so intense that the participant wants to avoid looking at it.

After the participant rated the first level, a technician increased the controller setting to level two. This process continued until the participant indicated the brightness was unbearable or the technician reached level six on the controller, the highest setting for the device. This process was then repeated at 150 ft for sign 1, 250 ft for sign 2, and 150 ft for sign 2.

Participants

The study recruited a group of participants approximately evenly distributed among males over 55years, females over 55 years, males under 55 years, and females under 55 years. Within each of those demographic groups, an even distribution between those who drove during the day and those who drove at night and between those who drove lap A first and those who drove lap B first was sought. These divisions resulted in 16 participant categories. The research goal was to have 4 participants in each of the 16 categories, resulting in 64 participants. The study included 71 participants because participants were added to 1) replace participants whose data were not recorded successfully and 2) provide additional data to offset missing data points not collected because signs were temporarily disabled or objects were not appropriately placed.

Results

The evaluation of the driving portion of the study focused on the legibility distance for the study assemblies (i.e., the distance away from the sign when the participant could correctly state the words or symbol on the sign), the detection distance to objects, and the accuracy of detecting the objects. The discomfort glare evaluation focused on participants’ ratings of discomfort for an LED-embedded sign assembly and two circular 8-inch beacons with each having six different levels of intensity.

Key Findings Regarding Legibility Distance

For the analysis that focused on legibility distance, which is the distance between the sign and the participant when the participant reads the message on the sign, results indicate the following:

  • As expected, the legibility distance for signs during the day is greater than the legibility distance for signs at night.

  • Younger driver legibility distance is greater than older driver legibility distance. Finding age to be significant indicates future studies need to consider older participants.

  • The type of assembly was significant at night and nearly not significant during the day. This indicates that the effects of the beacons/LEDs on reading the message on the sign are more influential during nighttime conditions, an expected finding.

Key Findings Regarding Object Detection Distance

For the analysis focusing on object detection distance, which is the distance between the object and the participant when the participant said “ped,” “can,” or “box,” results indicated the following:

  • As expected, there is a significant difference between day and night object detection distances. For example, the daytime detection distance to a pedestrian was on average 911 ft with a standard deviation of 539ft. During the night, the pedestrian detection distance had very different statistics: mean distance of 116 ft and standard deviation of 93ft.

  • Similar to legibility distance, there was a statistically significant difference owing to age during the daytime; surprisingly, the same finding did not occur at night. The nighttime condition seems to impede detection to a point that the effects of several variables are too small to detect in the experiment.

  • Certain assemblies were associated with shorter object detection distances. For daytime conditions, the detection distance to an object was shorter for the R-B than with the C‑B12, C-B8, or the R-A (statistically significant). During the nighttime, the detection distance to an object was shorter with the R-B than with the C-B12 (statistically significant). These findings indicate that characteristics of the R-B, such as the light intensity or the location of the beacon beneath the sign, might negatively affect a driver’s ability to see an object.

Key Findings Regarding Object Detection Accuracy

For the analysis focusing on the accuracy of detecting objects, which considered the number of objects missed by the participants, the results indicate the following:

  • As expected, there is a significant difference in the probability of missing objects between daytime and nighttime conditions. What was not expected was the magnitude of the difference. Overall, during the day, 1 in 23 pedestrians/trash cans were missed while at night 1 in 5 pedestrians/trash cans were missed.

  • For both daytime and nighttime conditions, the shape of the beacon did not matter; a similar probability of missing the object was present whether the beacons were circular or rectangular.

  • The location of the beacons (above or below the sign) was significant during the day but not at night. During the day, participants were less likely to miss an object when the beacons were above the sign.

Key Findings for Discomfort Glare Study

The data show that for all devices at all distances, the percentage of participants indicating the brightness of the lights from the beacons/LEDS is comfortable decreases as brightness increases, and the percentage of participants indicating the discomfort glare is unbearable increases as brightness increases.

The discomfort glare data indicate agencies should focus on meeting minimum intensity and place less emphasis on obtaining the brightest devices possible. When devices have intensities and optical powers close to the SAE minima, the probability of unbearable discomfort glare is less than 1 percent.

SUMMARY AND CONCLUSIONS FROM OPEN-ROAD STUDY

The open-road study was conducted to investigate 1) whether drivers yield differently to circular or rectangular beacons when used with a rapid-flashing pattern, 2) whether a driver is more likely to yield to a pedestrian when the rapid-flashing beacon is activated than when it is not activated, and 3) whether vehicle traffic volume affects driver yielding.

Both rectangular beacons and circular beacons were installed at 12 sites located in 4 cities (Milwaukee, WI; Flagstaff, AZ; Austin, TX; and College Station, TX). At half of the sites, the circular beacons were installed first while the rectangular beacons were installed first in the other half of the sites. The same flash pattern was used regardless if the beacons were circular or rectangular. The research team used a staged pedestrian protocol to collect driver yielding data to ensure that oncoming drivers receive a consistent presentation of approaching pedestrians.

Shape

Because a previous study that included RRFBs found that posted speed limit, crossing distance, and city influenced driver yielding, the initial analyses were conducted with those variables along with ADT, random effect for rotation order, and the beacon shape variable.(11,12) An indicator variable for nighttime conditions was included in the final model to determine whether nighttime results were significantly different from daytime results. The preliminary review of the findings (average daytime yielding was 63 percent for CRFBs and 59 percent for RRFBs) indicates only minor, if any, differences between the CRFB and the RRFB. The results from the GLMM further revealed that there were no significant differences between the two beacon shapes (p-value =0.4717). For a subset of the sites, the brightness of the beacons was measured. For those sites, there is clear evidence of an increasing yielding rate with increasing intensity at night. The trend is in the same direction during the day but with a smaller magnitude that the analysis found statistically insignificant.

Activation

An analysis was also conducted to determine the extent to which the presence of an actively flashing beacon influences driver yielding. Driver yielding rates were compared between pedestrian crossings when a beacon was activated and pedestrian crossings when a beacon was not activated. The analysis included RRFBs and CRFBs, staged pedestrians and nonstaged pedestrians, and daytime study periods. The results of the analysis concluded that a driver is 3.68times more likely to yield when the beacon is activated than when the beacon is not activated.

Traffic Volume

Based on observations of driver behavior during the data collection, the research team conducted an analysis to determine whether driver yielding was influenced by other vehicles in the traffic stream. The objective of the analysis was to evaluate the relationship between traffic volume and driver yielding rate. The analysis focused on a 1-min vehicle count. To estimate the traffic volume present when a particular pedestrian was attempting to cross, 1-min traffic volume counts were obtained from the videos for a sample of the daytime data collection periods at RRFB sites. The 5-min period nearest to when the pedestrian was crossing was averaged. The results of the analysis concluded that traffic volume was not significant, suggesting that driver yielding behavior was not influenced by traffic volume present at the sites.

Results

In conclusion, traffic volume and the shape of a yellow rapid-flashing beacon do not have an impact on whether a driver yields to a pedestrian. However, while the shape of a beacon does not influence driver yielding, a driver is more than three times as likely to yield when a beacon has been activated as when it has not been activated. Other variables that had an impact on driver yielding include beacon intensity (for nighttime) and city (yielding was higher in Flagstaff compared with the other cities included in study).

DISCUSSION

The STC of the NCUTCD is interested in research findings that could assist in crafting language regarding this device that would result in material suitably generic for the MUTCD. For example, as studied in this research project, do the beacons need to be rectangular or could they be circular?

In this study, the presence of beacons or LEDs was associated with shorter nighttime sign legibility distances. One interpretation of this finding could be to question the use of beacons because they affect the ability of a driver to read a sign. Even if flashing beacons limit the ability to read a sign, their presence can warn drivers to take additional care at the location. The presence of a yellow flashing beacon communicates warning to a driver and, perhaps, the need to look for unexpected entries onto the roadway. Unfortunately, the extensive and continuous use of the flashing yellow beacon on roadways might not effectively communicate to drivers the needed action of slowing down or searching for a potential roadway entry. The use of a specific flash pattern, however, could offset some of these concerns.

The brightness of the beacons can help draw a driver’s attention to a device and the area around the device. It can also result in drivers looking away from the device because the brightness is irritating or unbearable. As the brightness of the beacons on a traffic control device increases, the probability of a driver indicating the discomfort glare is unbearable increases. When the discomfort glare is unbearable, drivers are more likely to divert their eyes away from the discomfort, which might result in drivers missing hazards located near the glare source. The profession needs to identify maximum brightness for RRFBs. The profession also needs guidance on whether to dim these devices during low light conditions, and if so, by how much.

A part of the effort to set brightness levels is the need to investigate how best to measure the brightness of a flashing device. Peak intensity is not the only measure of brightness, and in some instances, it might not be the best measure of brightness. How to measure the impacts of different flash patterns that have unequal bright and dark periods must be considered.

The closed-course study demonstrated that fewer objects were missed when the beacons were located above the sign. It also found that both the daytime and nighttime detection distance was shorter, which is less desirable, to objects beyond an assembly with two rectangular beacons below the sign compared with other selected assemblies. Therefore, based on these findings, having the rectangular beacons located above the sign rather than below the sign should be considered.

The closed-course study also found that when grouping the beacons by shape (i.e., rectangular versus circular), there was no significant difference in object detection accuracy. Therefore, both beacon shapes were selected for study in the open-road portion of the project, and results indicated that there are no significant differences in driver yielding between the two beacon shapes. With the finding from the open-road study that the shape of the yellow rapid-flashing beacon does not affect a driver’s decision to yield, agencies could have the flexibility to use either shape with their pedestrian treatment installations, assuming that the appropriate language is included in the MUTCD. Another interpretation is that with both shapes having similar yielding, one shape should be selected and specified in the MUTCD to promote pedestrian treatment consistency.

In the open-road portion of this FHWA study, the brightness of devices installed in the field was also measured. The brightness of LEDs in the field appears to be highly variable; part of the reason could be that current requirements only specify a minimum intensity.

FUTURE RESEARCH NEEDS

In this section, a pedestrian rapid-flashing beacon assembly is assumed to consist of a Pedestrian Crossing (W11-2) or School Crossing (S1-1) sign and a pair of beacons (whether rectangular or circular) that flash in a rapid pattern. The rapid pattern could either be the 2-5 pattern, or the now preferred WW+S pattern as discussed in Official Interpretation #4(09)-41 (I)—Additional Flash Pattern for RRFBs.(43) The rapid-flashing beacon assembly can be located either roadside or overhead.

Based on the research conducted as part of this study, along with discussions held at professional society meetings and with other practitioners, additional research questions regarding rapid-flashing beacons used at pedestrian crossings are discussed in the following sections.

Appropriate Use of Rapid-Flashing Beacon Assemblies on Only One Side of the Roadway Approach

The original Interim Approval for the RRFB requires the following for assembly location:

For any approach on which RRFBs are used, two W11-2 or S1-1 crossing warning signs (each with RRFB and W16-7P plaque) shall be installed at the crosswalk, one on the right-hand side of the roadway and one on the left-hand side of the roadway. On a divided highway, the left-hand side assembly should be installed on the median, if practical, rather than on the far left side of the highway.”(1)

There may be street widths where having two assemblies provides limited benefits. If so, the additional cost savings in purchasing and maintaining fewer devices at a site could provide additional resources to treat other locations.

When Rapid-Flashing Beacons Should Be Dimmed, and by How Much

The profession needs guidance on whether to dim these devices during low light conditions, and if so, by how much. A study of disability glare and discomfort glare in both bright and dark conditions can be used to determine appropriate maximum nighttime and daytime brightness for rapid-flashing beacons. The investigation into brightness levels should consider an open-road portion to be able to associate different motorist yielding behavior with the different brightness levels.

Appropriate Brightness Level of Rapid-Flashing Beacons

The brightness of the beacons can help draw a driver’s attention to a device and the area around the device. It can also result in drivers looking away from the device because the brightness is irritating or unbearable. When the discomfort glare is unbearable, drivers are more likely to divert their eyes away from the discomfort, which might result in drivers missing people or objects located near the glare source. The results of this study indicate the profession might want to consider a maximum brightness for beacons used with pedestrian crossing signs—and the maximum brightness should vary between daytime and nighttime conditions.

Appropriate Installation of Rapid-Flashing Beacon Assemblies Overhead Rather Than on the Roadside

FHWA issued an interpretation in 2009 that indicated overhead mounting is appropriate and that, if overhead mounting is used, a minimum of only one sign per approach is required and it should be located over the approximate center of the lanes of the approach.(13) The catalyst for this interpretation was a concern that a frequent bus presence at a near-side bus stop would unacceptably obscure approaching road users’ view of the Pedestrian Crossing (W11-2) signs mounted at the normal roadside locations.

When Garland, TX, installed several RRFBs on multilane undivided roadways, city staff were concerned that the left-side roadside assembly would be outside the driver’s cone of vision or it could easily be obscured by a truck traveling in the opposite direction. Medians on divided roadways provide a location for a left-side beacon installation adjacent to traffic approaching the crosswalk, but roadways with narrow or no medians do not. Therefore, at crosswalks located on undivided roadways (e.g., four lanes and a TWLTL, multilane one-way roads) or roadways with a median less than 4ft wide, Garland installed RRFBs and School Crossing signs on a mast arm over the roadway. Garland also decided to supplement its overhead installation with roadside installations as illustrated in figure 2.

Presence of buses and street width are two examples of site conditions where the rapid-flashing beacon could be installed overhead rather than roadside, but there might be other criteria that should be considered when making this decision. In addition to identifying the applicable criteria, developing numeric guidance for these criteria is also needed (e.g., at what roadway width should overhead rather than roadside installation be considered). The guidance might also need to consider additional variables beyond primary characteristics such as roadway width. For example, if the sidewalks at the site are adjacent to the face of curb, then the roadside assembly might need to be located more than 5 ft from the curb, which would place the assembly beyond the driver’s cone of vision. Additional research is needed to investigate these questions.

Guidance on Selection of Appropriate Pedestrian Crossing Treatment for a Particular Location

In general, the pedestrian hybrid beacon has higher yielding rates but costs more than rapid-flashing beacon assembly. The rapid-flashing beacon is more effective than many other pedestrian treatments; however, a Texas study found lower compliance for the RRFB for longer crossing distances.(11) This finding indicates that there is a crossing distance width for which a device other than the RRFB should be considered. The dataset included sites with total crossing distances that ranged between 38 and 120 ft.

A research study with an objective of developing guidelines for selecting appropriate pedestrian crossing treatments would help to improve uniformity across the country. The study would also need to identify the site conditions that should be considered (e.g., roadway volume, pedestrian volume, crossing distance, posted speed limit, typical pedestrian walking speed at the site, and/or others). It could start with the methodology developed as part of NCHRP 562/Transit Cooperative Research Program (TCRP) 112, which uses pedestrian delay to make the determination of whether to recommend a device with a red indication (e.g., pedestrian hybrid beacon), a yellow indication (i.e., an active device such as a rapid-flashing beacon), or a crosswalk.(44) The method also includes a step to determine whether a traffic control signal is warranted. Figure 102 shows an illustration of a graph that can be generated from the NCHRP 562/TCRP 112 methodology using an assumed crossing distance and other variables. The user would then use the major road volume and the pedestrian volume to determine the appropriate type of pedestrian treatment for the site. The graph in figure 102 is out of date because the research was done prior to the 2009 MUTCD change in the pedestrian signal warrant, but the concept is applicable.

Figure 102. Graph. Example of graph generated from NCHRP 562/TCRP 112 (43) methodology (function of walking speed, crossing distance, and other variables) that could be used to determine pedestrian treatment. The graph shows the suggested pedestrian crossing treatments from National Cooperative Highway Research Program Report 562/Transit Cooperative Research Program Report 112 for various combinations of pedestrian volumes crossing the major road in pedestrians per h (on the y-axis) and major road volumes in vehicles per h (on the x-axis). Five treatment categories are represented: traffic signal, red device, active/enhanced yellow device, marked crosswalk, and no treatment. Except for signals, each treatment has a maximum boundary line plotted on the chart; below that line, the plot area is shaded with a color or pattern corresponding to that treatment: black diagonal lines for red devices, dark gray shading for enhanced devices, light gray shading for crosswalks, and white for no treatment. The plot area above the boundary for red devices is patterned with small black dots on a white background and represents the conditions for which a traffic signal is recommended.

Figure 102. Graph. Example of a graph generated from NCHRP 562/TCRP 112 methodology (function of walking speed, crossing distance, and other variables) that could be used to determine pedestrian treatment.(44)

National Education Campaign on the Rapid-Flashing Beacon

What education campaigns have been used by cities and jurisdictions that have implemented rapid-flashing beacons? Were they successful? Are there common themes that could be used on a national level? The campaigns could also include other considerations of pedestrian behaviors such as the need to activate the pushbutton, cautions against distracted walking, walking during nighttime conditions, blind spots around commercial vehicles, and others. Education campaigns could be directed toward drivers, pedestrians, or both.

Minimum Number of Pedestrians to Warrant a Pedestrian Treatment

There is a growing use of the pedestrian hybrid beacon and the RRFB for pedestrian crossings. Establishing guidance that can be consistently applied would help to facilitate use of these devices in appropriate settings. A particular question is whether there is a minimum number of pedestrians before a device should be considered. The MUTCD contains graphs that illustrate when to consider a pedestrian hybrid beacon, and these graphs include a minimum of 20pedestrians per h.(2) When deciding to recommend this minimum pedestrian number, the National Committee based its decision on a value developed through engineering judgment during an FHWA study on whether to mark crosswalks.(45)

Research is needed to more fully consider what should be the minimum pedestrian value used for selecting various traffic control devices. For example, should this minimum number be a function of crossing distance or posted speed limit? In addition, should it consider the distance to the nearest crossing? A location that is only a few hundred feet from an established crossing should have a higher minimum number compared with a crossing that is more than 0.25 or 0.5mi from a signal on a wide high-speed arterial.

Number of Pedestrians Induced as a Result of Installation of Selected Pedestrian Treatments

The primary objective of this study would be to determine reasonable values for estimates of induced pedestrian crossing maneuvers (i.e., estimated number of pedestrians that would now use the site because of the installation of a specific pedestrian treatment). The results of the research could improve the process for selecting pedestrian treatments. The research should make appropriate suggestions for changes to key reference documents, such as design manuals or the MUTCD. Improved guidance should help to improve conditions for pedestrians by identifying appropriate devices for crossings, which should improve pedestrian mobility and reduce the number of pedestrian crashes.

Drivers’ Search Patterns Near Flashing Beacons

There was also evidence in this study that the closed-course drivers were more accurate in seeing objects beyond the signs with flashing beacons compared with seeing objects beyond the distractor signs. This could be an artifact of this study or it could be because the flashing beacons attracted the eye to the area. Additional research could focus on drivers’ search patterns when a flashing beacon is present to test the theory that the presence of the beacons or LEDs encourages drivers to search a particular area. By varying the brightness of the beacons along with the light source (e.g., beacons or LED-embedded signs), the study could also investigate whether drivers need additional time to search an area because of the brightness of the device.

Pedestrians’ Attitude Toward Using Treatments

Observations of pedestrians in the open-road portion of this study (and in other studies) have documented crossing pedestrians that did not activate the beacon when it was provided. Some of those pedestrians were jaywalking and were not within the treated crosswalk to be able to use the beacon, while others crossed at the crosswalk but chose not to activate the beacon. This study would explore pedestrian decision-making and examine why pedestrians who have the opportunity to use a treatment (such as a rapid-flashing beacon) to support their crossing choose not to do so. For example, at crosswalks marked as school crossings, do adult pedestrians think that the treatment is for use only by schoolchildren? Results from this study could feed into the suggested educational campaign mentioned previously, and results could also be used to support guidance on where treatments should be installed and what information (e.g., instructional plaques next to the pushbutton) should be provided to crossing pedestrians.

Influence of Traffic Volume on Driver Yielding

In this research, an analysis was conducted using RRFB sites to evaluate the relationship between traffic volume and driver yielding rate. While the plot in figure 101 suggests that the percentage of driver yielding might decrease as volume increases, that relationship was not statistically significant. In other words, there was not enough evidence to conclude that traffic volume influences driver yielding behavior at sites with RRFBs in a positive or negative direction. However, the percentage of driver yielding varied substantially between cities, and this city-to-city variability might have had a stronger influence on the model than traffic volume. Additional research with larger sample sizes and/or additional cities is needed to look at the relationship between traffic volume and driver yielding more closely.

Estimating Pedestrian Exposure

With average daily vehicle traffic being the key predictor of vehicle crashes, there is a desire to have similar types of data for pedestrians. With limited resources for collecting counts—vehicle, bicycles, or pedestrians—what are the most effective means for obtaining pedestrian exposure?

 

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