Dissertation Summary
Paper Title:
A study on the lighting environment to improve crime prevention safety in streets
The majority of public spaces in Japan have been planned in such a manner as to maintain the horizontal lighting level and vertical illumination level in street environments at levels laid down in the JIS lighting standards, in order to make them safe and reassuring. However, it is a fact that the relatively small number of lighting standards do not deal well with the great variety of circumstances in which they are must be applied. In particular, one could fault the way in which, in street planning, simply making areas well lit is taken as being a sign of economic development. Asking what actually constitutes an appropriate light environment, I return to first principles and, on the basis of basic physical issues such as whether people can see clearly or not, and walk safely or not, continue my experimentation and research. In this manner, I hope to address what I consider to be the necessity of constructing new light environments.
If one considers what types of action people take in a certain place, the type of light that is really necessary becomes clearer. For example, if a pedestrian is walking along a level path, then even if the path in question is not particularly well lit, the presence of sign-type lights to show the pedestrian where they are and where they need to go will allow them to get there without difficulties. It can be said that the shared spaces of housing projects have both public and private sections. In the public areas, it is necessary to take into account the prevention of interpersonal crime. However, in recent years, such housing has been fitted with security systems preventing the entrance of anyone not living in the project in question. As such, their shared spaces now have need of a light environment that matches the activities people engage in in private spaces. For the middle of the night when inhabitants are asleep and other similar times, such areas need light environments with high crime prevention characteristics. In contrast, during those times when inhabitants are still awake, crime prevention is a less important consideration.
Against this background, I have been active in researching the possible forms of new light environments that are not dependent on the use of street lamps. Since 1999, I have been conducting lighting experiments based mainly around pedestrian lighting in cooperation with the inhabitants of Kawagoe-shi in Saitama, Motomachi in Yokohama-shi, Ono-mura in Iwate-ken, Hachio in Toyama-ken, and Shirakawa-mura in Gifu-ken. Proposals have been developed for high crime-prevention light environments which made use of the light in building entrance areas. With regards to lighting environments for the road system, proposals have been developed to try and improve drivers' danger anticipation in namie-machi in Fukushima-ken and arai-machi in Shizuoka-ken. These new lighting techniques provide a new basis for energy-efficiency measures, while also reducing equipment costs and allowing the creation of safer and more comfortable urban environments.
By taking as its subject real urban environments, this research clarifies the individual characteristics of the regions in question without relying on the traditional street lamp standards. In this manner, and using surveys, light environment experiments, and experimental evaluation of their effects, the potential of urban environments at night has been demonstrated. It is the opinion of the current author that this work is significant in that it constitutes a new process for realizing a more appropriate type of area-specific urban lighting.
In Chapter 2, in pedestrian function performance lighting, I investigated the bare minimum light environment required for pedestrians to navigate an area. With surveys conducted as part of a plan implemented at the Saitama New Downtown Pedestrian Deck, I verified the pedestrian usability of the flat areas, which are part of the Barrier Free program. In addition, in lighting experiments at bridges and other spatially-simplified walkways, I established experimentally that the amount of lighting required was less than had previously been thought. It was also observed that, irrespective of how advanced Barrier Free developments became in any city environment, the reality is that elevation differences still exist to some extent, such as at steps. For this reason, I researched where people look and how they make judgements at such points. I also analyzed pedestrian functions in the shared areas of public housing. It is my intention to take as one of our policies this type of discovery of how to produce light environments which provide the bare minimum of light required by pedestrians. As a result of the foregoing, we established that people tend to hardly look at the ground at all once they have established to their own satisfaction that the area they are walking in is flat. Pedestrians needed signs telling them where they were and where they needed to go to navigate effectively. It was also clear that, in areas with elevation differences, signs were needed to give pedestrians a real spatial grasp of the difference in question. How best to actually achieve this became clear through our research.
In Chapter 3, I considered street area Boyd lighting as a physical component in creating reassuring street spaces for pedestrians. Areas where the street dips relative to its surroundings are known as Boyds. Analyzing the elements that are most responsible for pedestrian uncertainty at night, we discovered that Boyds play a key role in reducing confidence in this regard. By producing a model based on actual street environments, I ascertained exactly what the causes of uncertainty were via experimental simulations of night-time light environments. My surveys at Nakadouri, Motomachi, had indicated to me that switching off the crime prevention lights fixed to the telegraph poles in the area had no effect on the degree of confidence felt by pedestrians moving through the area. This established that their installation in the area had no effect. Having established that installing crime prevention lights in an area would not necessarily improve its crime prevention capabilities, I investigated the spatial characteristics of Boyds. In Omura, Iwate-ken, I considered the entire urban planning process, from surveys to experiments, and from inspection to design, all the way though to implementation. After this, I inspected a variety of street areas, and conducted onsite experiments in such locations as Hachio-shi, Toyama-ken, and the Hirose area in Shirakawa-mura, Gifu-ken, to determine the efficacy of Boyd lighting. This study demonstrated that brightness of the area as a whole was not desirable in its own right. Rather, point lighting proved to be more effective in giving pedestrians an awareness of the space they were passing through, with pedestrian focus on the points creating a greater sense of security. It can thus be seen that Boyd awareness is effective in reassuring pedestrians through giving them a greater awareness of the space they are passing through. The single most important factor in giving pedestrians confidence is an awareness of the presence of other people. It is vital for people to be able to discern the silhouettes of others in Boyds, where it is easier to hide than in flat areas, if they are to be confident in their surroundings. There is a limit to how wide a Boyd can be and still have effective Boyd lighting, which does not have a range of greater than approximately 25m. Boyd lighting can make urban surroundings seem well-lit, and therefore allows us to increase visualization of the urban landscape. Lastly, I determined that, in the areas I investigated in this paper, Boyd lighting is superior at giving pedestrians a sense of confidence in their surroundings than standard street lamps.
In Chapter 4, I discuss on-site investigations at Ichiban Machi-dori in Kawagoe-shi and Hachio-machi in Toyama-shi which demonstrated that pedestrians are given confidence by the light emitting from the windows near building entrances in street areas due to the sense of a human presence they create. I conducted experiments in Hachio-machi in Toyama-shi to determine just how effective window lighting could be in this regard, and used these results to formulate the appropriate response in this area. This made it clear to me that window lighting had utility in crime prevention and that ground-floor window lighting was most useful in this regard. Lights indicative of human presence such as gate lights and porch lights also showed this effect, demonstrating that it is generally true that anything that brings a sense of human presence to streets gives pedestrians confidence. The lighting systems produced also gave their respective areas an attractive look.
In Chapter 5, I look at traffic intersections from the viewpoint of danger anticipation. Continuing to apply the pertinent areas of the Road Lighting Installation Standards, I looked into light environments that would improve the danger anticipation of drivers at intersections. These investigations demonstrated the strong influence that spatial factors, road signs, and road markers have on the awareness of drivers at intersections, and also established that it is possible to use the urban layout itself to enhance intersection awareness. Lighting that aids in danger anticipation reduces the frequency of traffic accidents, while also reducing the severity of those accidents that do occur.
None of our research would have been possible without the cooperation of the inhabitants of the relevant areas, without their understanding, or if they were to derive no benefit from it. The great advantage of light in constucting urban environments is that, in comparison with road and pavement maintenance, it provides significant benefits relative to its costs. In Ono-mura, the recent light environment installation work was the start of something more, as was demonstrated by the formation of an urban renewal committee. This committee now proactively generates proposals for the use of empty houses and empty lots. Also important is the way in which thinking about light provides the opportunity for people to reexamine their own lives and their own home areas. Prospective street maintenance plans are difficult for people to understand, but light is easy to grasp from our own experience. Having been able to pursue these projects while making efforts to bring all these advantages of light together, I succeeded in bringing them to fruition.
From now on, a shift from specification design to performance design will be required. Light is the perfect medium for this switch, incorporating the characteristics of a given region as it leaks out of people's everyday lives into our urban environment. Light needs to be established as a shared system of values that anyone can choose and understand. In the case of lighting, the cooperation of the power companies is essential. In Ono-mura, park lights installed in public housing areas were also used as public street lamps. I would like to propose time-based operation for these lights in line with the activities of the people in question, as the priority accorded to crime prevention when women may be walking by themselves at night will not be appropriate when people are awake.
Light planning involves many elements that cannot be correctly set by trying to follow a set of rules. I hope to be able to create a unique night-time environment for Japan by steadily adding to the number of fine examples of good light planning across the country.
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