Human Factors Assessment of Pedestrian Roadway Crossing Behavior

Discussion

An overarching goal of the present study is to determine which environmental factors influence where pedestrians cross the roadway. In phase 1 of this study, pedestrian crossing behaviors were recorded and coded over a 2-week period at eight different locations. It was hoped that these data would help to identify factors that influence pedestrians to cross at unmarked non-intersection locations. Furthermore, it was hoped that these data would produce a model that might predict pedestrian crossings. However, of the total 65,725 crossings, only 4,399 (or 6.7 percent) took place in an unmarked non-intersection location. In other words, these crossings are generally rare events. As a result, the number of location areas limits the statistically appropriate modeling techniques available. These methodologies were unable to successfully model the pedestrian crossing data from these eight locations.

To attempt to more accurately model and predict pedestrian crossing behavior, data from an additional 12 locations were collected. These data are described further in phases 2 and 3. Here, the data and trends for the eight locations from phase 1 are discussed.

Crossing Location

As noted previously, few crossings took place in an unmarked non-intersection location. Overall, only 6.7 percent of the crossings occurred outside an intersection (marked or unmarked). Another way to examine these crossings is to explore the distributions of crossings at each location. Location 8 is considered an outlying value, with 28.2 percent of the crossings occurring at unmarked non-intersection areas. This warrants further discussion about the characteristics of Location 8 that might cause this result.

The distance to the next marked crossing for Location 8 was approximately 433 ft. This location is not considered an outlier (nor are any of the other locations) in the current eight locations, which have a mean distance of 418.9 ft. The AADT value of 21 is not considered an outlier (nor is the AADT for any of the other locations) in the current eight locations, which have a mean of 20.7. The eight locations also did not significantly vary in the length of the walk phase, the length of the don’t walk phase, or the width of the crossing. As such, it is not likely that any of these factors alone caused the above average number of crossings at an unmarked non-intersection.

Location 8, however, does require pedestrians to travel at a speed of 3.7 ft/s to cross in the marked intersection entirely during the walk light phase. This rate is greater than the Manual on Uniform Traffic Control Devices (MUTCD) recommended rate of 3.5 ft/s. Furthermore, the MUTCD states, “Where pedestrians who walk slower than 3.5 ft/s, or pedestrians who use wheelchairs, routinely use the crosswalk, a walking speed of less than 3.5 ft/s should be considered in determining the pedestrian clearance time.”⁽²⁸⁾  Given that there is an elementary school approximately two blocks away from this intersection and that there are small suburban type establishments (including a church, neighborhood market, and library) in the general area, it is likely that there is substantial pedestrian traffic near this intersection that regularly travels at a rate of less than 3.5 ft/s.

Although pedestrians were not specifically queried about their crossings, it is possible that pedestrians may feel rushed while crossing at the marked intersection. This rapid pace required to cross at the marked intersection during the walk phase may lead pedestrians to feel hurried and uncomfortable crossing at this location. This intersection is also just outside a traffic circle. This location prevents pedestrians from being able to see traffic from a distance adequate to determine whether a vehicle will continue traveling within the traffic circle or exit toward the intersection. Furthermore, this location reduces pedestrians’ abilities to confidently determine whether the vehicle will cross their potential path during a crossing that takes place (at least partially) during the don’t walk phase (a scenario that is likely if the pedestrian is not already waiting at the intersection and can cross at a rapid pace). This time pressure, combined with a long wait time for the next walk phase (79 s), may encourage pedestrians to cross outside this marked intersection.

As noted previously, perceived control of a situation influences pedestrians’ intentions to cross the roadway. Given the short crossing time and pedestrians’ inability to confidently predict behavior of traffic exiting from the traffic circle, it is possible that pedestrians may feel that crossing at unmarked non-intersection areas increases their control of the situation (i.e., perceived control). Moving south of the marked intersection to cross the roadway provides pedestrians the opportunity to see bi-directional vehicle travel from a greater distance and to potentially find longer gaps in traffic to permit crossing at a more leisurely pace. In addition, the next marked crossing is not light controlled. As a result, pedestrians must still find an appropriate gap to cross traffic, and consequently using that marked crossing is not likely to present a greater level of perceived control. As such, crossing at an unmarked non-intersection may optimize pedestrians’ perceived control and perceived time efficiency in crossing the roadway.

There were no outliers in terms of the lowest percentage of crossings at unmarked non-intersection areas. However, Location 7 did have the lowest percentage, only 3.0. This low value is likely the result of a several factors. First, the distance between the marked intersection of interest and the next marked crossing is only 145 ft. While this is not an outlier, it is the most extreme value at 1.7 standard deviations below the mean value of 418.9 ft. Furthermore, there are few trip originators or destinations. Along the east side of the block is a park. However, shrubbery blocks entrance along this side, and pedestrians need to go to an adjacent side of the park to obtain entry. In other words, crossing the road between the two marked crossings does not provide an advantage in gaining entrance to the park. Along the west side of the block, there is a single large office building. Although it was not specifically recorded, anecdotal evidence suggests that most pedestrians who crossed at an unmarked non-intersection area were traveling to or from this office building. Furthermore, along this west side of the block, there are several large flower planters and concrete benches (that face away from the roadway). These objects do not prevent pedestrians from crossing in this area, but they do impede a simple and direct travel path from the sidewalk to the roadway. It is likely that the concrete structures deter pedestrians from crossing outside the nearby marked crosswalks.

At both Location 7 and Location 4, more than 90 percent of the crossings took place within the marked intersection. These two locations also had the two highest percentages of crossings that took place in the marked intersection during the don’t walk light phase (17.9 and 18.7, respectively, compared with an overall mean of 6.9). As a result, it is important to explore the factors that might influence these crossings. At both locations, there is a left turn arrow that guides traffic through the marked intersection that might be difficult to see from the pedestrian’s perspective.

At Location 7, Pennsylvania Avenue Northwest travels east/west, just north and perpendicular to the marked intersection of interest. Prior to the walk phase, vehicles traveling west on Pennsylvania Avenue are given a green arrow to turn south—turning through the marked intersection. However, pedestrians traveling east at this intersection cannot see that the left turning vehicles have a green light. Instead these pedestrians can see that cross traffic has a red light and that the opposite walk signal has just turned from walk to don’t walk. As such, pedestrians here may incorrectly assume that it is safe to begin crossing, perhaps presuming that the light is simply in the “delay” time period, and they anticipate that it will turn to the walk phase shortly after entering the crosswalk. Again, it should be noted that pedestrians were not asked about their crossings. However, given the unique characteristics of this crossing location, this is a reasonable and logical explanation of the pedestrian crossing behavior.

At Location 4, 13th Street Northwest travels north/south, just east and perpendicular to the marked intersection of interest. Just after the conclusion of the walk phase, vehicles traveling north on 13th Street are given a green arrow to turn west—turning through the marked intersection. However, pedestrians traveling south at this intersection cannot see that the left turning vehicles have a green light and may incorrectly assume that the vehicles have a red light and will stop. Similarly to Location 7, pedestrians here may think that it is safe to cross the roadway, when indeed this may not be the case.

Location 3 had a large proportion of pedestrian crossings at an unmarked intersection. In fact, pedestrians were approximately equally likely to cross at the unmarked intersection as the marked intersection. This finding suggests that pedestrians perceive the unmarked intersection to be a safe, and acceptable, place to cross the roadway. Although the traffic light phasing was not set to incorporate pedestrian crossings, pedestrians took advantage of the median separating east and west traveling traffic. Given that 41 percent of the crossings at the unmarked intersection involved waiting on the median, it appears that pedestrians were not trapped on the median as previous research has reported. Rather, at this location pedestrians plan their crossing in phases; crossing a segment and waiting on the median and then completing the crossing. This is a tactic that presumably increases perceived control.

Beyond the ability to divide the crossing into two portions, environmental factors both encourage crossing at the unmarked intersection and discourage traveling to the marked intersection. Pedestrians traveling to/from the north side of Rhode Island Avenue and Marion Street are required to travel out of the way to cross at the marked intersection. This is a result of the juxtaposition of the streets. Rhode Island Avenue is a “diagonal” street. This means that pedestrians need to travel south along Rhode Island in addition to west to reach the marked intersection, when traveling north. (When traveling south, pedestrians must travel farther south than desired and then return north while traveling east to reach Marion Street.) Furthermore, the marked intersection involves three segments (crossings at only the center and main segment were specifically counted in this study), which, combined, are wider than the single unmarked intersection. Each segment is divided by a concrete median/island that includes a separate crosswalk signal. This means that it is possible to begin crossing the street in one light phase, but the pedestrian may need to wait on a median/island until the next light phase to complete the crossing. To pedestrians, these two factors combined may outweigh the potential benefits of crossing during a protected light phase—especially given the relatively rare occurrence of a vehicle–pedestrian collision. In addition, the unmarked intersection has several factors that afford a crossing. It is obvious that this is at an intersection—a location where most marked crossings are found. Further, this location lies at a junction where it is natural to want to travel. There is Metro station only one block west of the marked intersection, on the north side. As a result, crossing at the unmarked intersection when traveling to/from the Metro station, along Marion Street, is likely the most direct and efficient route. Finally, the median in the unmarked intersection looks like a sidewalk. Pedestrians can clearly see a concrete area on the end of the median that is approximately the width of a standard sidewalk (e.g., a firm, raised surface that serves as a barrier from roadway vehicles). As such, this area affords the same things to pedestrians as a standard sidewalk. It is likely that pedestrians interpret use of this area as they would any other sidewalk area.

Pedestrian Yielding

In total, 298 of the 65,725 crossings (.45 percent) involved pedestrian yielding. Overall, the mean percentage of pedestrians who yielded to vehicles was .53 (i.e., the mean of the percentage of pedestrians who yielded to vehicles at each location).

Overall, Location 3 had a significantly greater percentage of pedestrians who yielded to vehicles. However, this value is inflated owing to the crossings that occurred in the unmarked intersection location. As a result, of this unique crossing situation, Location 3 is not discussed further here.

The mean percentage of pedestrians who yielded to vehicles in the marked intersection was .19. Location 7 was an outlier in the percentage of pedestrians that yielded to vehicles, with 2.42 standard deviations above the mean. This area had a substantial number of vehicles turning right and passing through the intersection. While the exact circumstances of each yielding behavior were not recorded, it was noted on several occasions that pedestrians would allow vehicles to pass to relieve vehicle congestion. In other words, a pedestrian(s) would allow vehicles to complete a right turn so that other traffic traveling straight through might pass. There were also several instances where a left-turning vehicle yielded to a pedestrian while the vehicle had a protected turn (i.e., a green left turn arrow), but was left in the intersection when oncoming vehicular traffic started flowing. In these circumstances, pedestrians often yielded to vehicles during the walk phase to allow the vehicle to complete the turn and avoid traffic delays.

Overall, significantly more pedestrians yielded to vehicles in the unmarked non-intersections than in the marked intersections. This suggests that pedestrians who cross outside the marked intersection are more likely to encounter a situation that requires yielding to avoid collision.

Vehicle Yielding

In total, 9,385 of the 65,725 crossings (14 percent) involved a vehicle yielding to a pedestrian. Overall, vehicle yielding did not vary by pedestrian crossing location. The mean percentage of drivers who yielded to pedestrians was 9.77 (i.e., the mean of the percentage of vehicles who yielded to pedestrians at each location). Overall, Location 7 (38.7 percent) had a significantly greater percentage of vehicles that yielded to pedestrians. As noted in the previous section, a large number of vehicles turned through the marked intersection area at Location 7. As a result of the turning traffic having a green light and the pedestrian signal in the walk phase, vehicles often waited to complete their turn (i.e., yielded) while pedestrians crossed the roadway. A similar situation to Location 7 presents itself at Location 4. At Location 4, right turning vehicles have a green light at the same time that the pedestrian signal is in the walk phase. As a result, vehicles often waited to complete their turn (i.e., yielded) while pedestrians crossed the roadway.

Yielding Comparison

A surprising result is that there is no significant difference in the percentage of pedestrians who yielded to vehicles and the percentage of vehicles that yielded to pedestrians during the walk phase in the marked intersection. One would expect that few pedestrians would yield to vehicles. This lack of a difference could be the result of several factors.

It is possible (and likely) that pedestrians are aware of the extreme traffic congestion in Washington, DC. This may lead them to intermittently allow vehicles to complete turns, which allows following traffic to continue straight and subsequently alleviates minor intersection congestion. It is also possible that pedestrians simply feel safer in allowing the vehicle to turn prior to completing their crossing. In other words, if a pedestrian–vehicle collision were to occur, it is more likely that the pedestrian would be injured than the driver of the vehicle, even at low speeds. As a result, pedestrians may simply be exhibiting caution.

Evasive Pedestrian Actions

In total, 1,862 of the 65,725 crossings (2.83 percent) involved an evasive pedestrian action. Overall, the mean percentage of pedestrians who took evasive actions was 4.39 (i.e., the mean of the percentage of evasive pedestrian actions at each location). The percentage of evasive actions was fairly consistent across locations and across crossing types. At the present time, the data do not suggest any clear environmental reason for these evasive pedestrian actions.

The percentage of evasive pedestrian actions did, however, vary by pedestrian crossing location. Pedestrians were more likely to take evasive actions in the unmarked non-intersection areas than the marked intersection. Likewise, pedestrians were less likely to take evasive actions while crossing entirely during the walk light phase in the marked crossing than in all other crossings.

Evasive Vehicle Actions

In total, 12 of the 65,725 crossings (.02 percent) involved an evasive vehicle action. Overall, the mean percentage of vehicles that took evasive actions was .05 (i.e., the mean of the percentage of evasive vehicle actions at each location). The only evasive vehicle actions took place in Location 1 and Location 2. This, combined with the small total number of vehicle evasive actions, does not provide the opportunity to make inferences at this time.

Further, the percentage of vehicle evasive actions did not vary by pedestrian crossing location. That is, vehicles were equally likely to take an evasive action in the unmarked non-intersection as in the marked intersection.

Evasive Action Comparison

In all crossing locations, pedestrians were more likely to take an evasive action than vehicles. This suggests that pedestrians may take a proactive approach to increase their safety by evading potential collisions with vehicles.

General Discussion

In the present set of data, non-intersection crossings are relatively rare. This makes it difficult to make predictions about where pedestrians will cross the roadway. Furthermore, of the 65,725 coded crossings, there was only a single close call/near miss. This near miss occurred at Location 7 during the walk phase in the marked intersection. In this instance, two pedestrians were about to enter the roadway while at the same time, a vehicle began to make a right turn (passing through the marked intersection). One person pulled the other person back to the curb. Although it is not clear from the video, it appears that the vehicle may have nearly collided with the pedestrian had he or she not been pulled back to the curb. Despite the pedestrian having the right of way in this case, it is easy to understand why the driver continued with the right turn. Prior to the pedestrians attempting to cross the roadway, they stood on the curb facing the opposite crossing direction (i.e., facing north, rather than east). Furthermore, the walk phase had been initiated for more than 10 s prior to the pedestrians attempting to enter the marked intersection. These clues could easily lead a driver to interpret the pedestrians as not a potential hazard.

The subsequent sections discuss data collection and findings from phases 2 and 3.