Pedestrians visibility

In fact, even when we look for a pedestrian and the pedestrian is in the lane we sometimes fail to see him or her. This has happened independently to Allen et al. (1970), and to me while conducting research on nighttime pedestrian visibility. That means that even when we are aware of the possibility of an obstacle on the road, such as a pedestrian, and even when we are actively searching the road to detect that obstacle, there is still a good chance that by the time we detect it (or him or her) we will not have sufficient time to stop and avoid a collision. Why or how does that happen ... 

To understand what it takes to see the pedestrian, the first thing we must do is define visibility. Langham and Moberly (2003) reviewed 16 studies of pedestrian visibility and noted that it is... 

Figure 15-9. Actual pedestrian visibility distances and pedestrians estimate of their visibility distance in high and low beams, with and without glare from an opposing car (from Shinar, 1985, with permission from the Human Factors and Ergonomics Society).

As a final comment on pedestrian visibility, it is interesting to point out that there is one group of pedestrians who are very sensitive to their visibility road work crews. These people always were reflective vests with retro-reflective materials when out on the road, and whenever... 

Shinar, D. (1984). Actual versus estimated nighttime pedestrian visibility. Ergonomics, 27, 863-871. 

Shinar, D. (1985). Effects of expectancy, clothing reflectance, and detection criteria on nighttime pedestrian visibility. Hum. Fact, 27, 327-334. 

All relevant processes are modeled and linked with realistic probability distributions. Each parameter is drawn randomly with respect to its probability distribution and possible dependencies on other factors in the simulation. The implemented scenario is an urban crossing scenario, as this is the most important one (see Sect. 3.2). The pedestrian crosses the street (straight road) from the right to the left from the view of the driver in the middle of a block. From the pedestrian s point of view, the traffic comes from the left. Scenario parameters include, for example, the geometry of the sidewalk, speed limit of the street or visibility restrictions. The traffic on the road itself is implemented as an exposure model depending on time of day and day... 

The vehicles in the simulation move on a straight street and have dimensions typical for mid-size vehicles. The braking capabilities are typical for up-to-date vehicles and typical road surfaces. The implemented preventive pedestrian protection system is thus modeled as part of the vehicle. Once the pedestrian is visible for the system, the probability per unit time that the pedestrian is detected by the system is modeled as a constant. The algorithm of the system includes a prediction of the vehicle s movement and the pedestrian s movement as well as the calculation of a collision probability as basis for a system action. The system itself has various stochastic components, e.g., inaccuracies regarding position and speed of the pedestrian. Depending... 

Within the last decade, pedestrian impact requirements have begun to play a visible role in automotive design. The front and hood portion of cars has effectively grown in volume to allow for deformable zones to absorb impact from pedestrians based on lower leg, upper leg, torso, and head impacts. 

Poor visibility to mini-roundabout signs (and to the belisha beacon and pedestrians)... 

Designers may wish to use dark-coloured signposts and bollards while Road Safety Auditors want to see reflective bands to make them more visible to visually impaired pedestrians. 

Traffic routes and loading and storage areas need to be well designed with enforced speed limits (a maximum of 10 mph is the limit on most sites), good visibility and the separation of vehicles and pedestrians being considered. The use of one way systems and separate site access gates for vehicles and pedestrians may be required. Finally, the safety of members of the public... 

The placement of physical features, activities, and people in a way that maximizes visibility is one concept directed toward keeping intruders easily observable and therefore less likely to commit criminal acts. Features that maximize the visibility of people, parking areas, and building entrances are unobstructed doors and windows, pedestrian-friendly sidewalks and streets, open entry areas, and appropriate nighttime lighting. 

Sayer, J. R. and M. L. Mefford (2004). High visibility safety apparel and nighttime conspicuity of pedestrians in work zones. J. Safe. Res., 35, 537-546. 

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