Introduction As shoppers stroll down the streets of Les Halles, they often ignore one of the most crucial aspects of city design: street furniture. Ranging from foliage lining the streets to benches filling the park, street furniture includes anything located between buildings and streets for public use.
An example of the diversity of bicycle racks, foliage, lamps, and benches in Les Halles.
Tasked with analyzing street furniture, we began by charting the quantity of each type. We found an abundance of trees and lamps in contrast to a scarcity of benches and bicycle racks.
The many styles of lamps observed and their relative abundance motivated our decision to study lamps in greater detail. Furthermore, in 2012 the US Bureau of Diplomatic Security cited Les Halles as an area to avoid at night. Moreover, as a center of the Parisian public transportation system, Les Halles has been labeled as a hub for organized crime and violence, with 5,065 reported crimes and offenses in 2013. With this high rate of crime, proper lighting at night is crucial to repair the area’s reputation. As a result of our own observations and the city’s safety concerns, we chose to analyze the light intensity throughout Les Halles. Methodology Initially, we hoped to study light intensity using a device acquired from the Open Lab in conjunction with the open source program Arduino. However, the device failed to properly transfer information to the program.
The device initially used to measure light intensity.
In light of this malfunction, we turned to available mobile applications. After recognizing the lack of precision in the myLightMeter Free application, we chose to use Pocket Light Meter, which provided consistent results across multiple trials. Using this application, we first measured light intensity in lux (J/m2 ) from the ground as a proxy for street illumination and safety, as this measurement incorporated the total amount of light emitted from public lamps and private businesses. Next, we took the measurement with the device directly facing the lamp to measure the lamp’s individual strength. Each measurement was taken from a distance of 1.60 meters from the lamp post.
Examples of the measurements taken via the application.
Data and Analysis On the date of observation, we found that all lamps throughout the area turned on exactly ½ an hour after sunset. Using our application, we also found that the different types of lamps each registered different lux values. This wide spread of values was surprising and led to noticeable differences in lighting throughout the area. We believe that the available technology at the time of lamp installation may explain the difference in lux between newer and older lamp types.
|Location||Directly (lux)||Floor (lux)|
|Nelson Mandela Park||72||11|
|Rue Rambuteau||32||Shop Interference|
|Rue Rambuteau 2||48||12|
|Fountain of Innocents (Outer ring)||72||11|
|Fountain of Innocents (Inner ring)||38||20|
|Rue Berger 23||199||28|
|Les Halles Arch||145||90|
The floor lux data support our observation that most streets in the Les Halles area were well-lit. In most regions, the floor lux levels were higher than 10 lux. We observed outlier values near the church, which contained a low concentration of lamps, and outside of the Camaieu shop, which was brightly lit. The data we collected is plotted on the below map, which acts as a testament to the Mayor of Paris’s efforts to transform Les Halles into a safer space at night. We hope that this project will serve as a template for other light maps of Paris. By crowdsourcing data from citizens, these light maps could help city officials recognize the more dangerous dark zones by looking at the total lux per street or area. Using this open-loop system, these officials could better target future light fixture projects.Improvements Our aim is to improve energy efficiency without compromising safety. The light grid system in Les Halles is currently activated by a combination of timer and light sensing devices. Based on our observations between sunset and the turning on of the lamps, this current system is effective. However, we observed similar lux readings in lamps near high-lux storefronts and low-lux storefronts, and we feel that this lack of flexibility represents a major flaw. Thus, our suggestions build on those proposed by la Mairie de Paris to be implemented within Les Halles to establish varying light intensity. More specifically, in the shopping complex, the lights sense the level of natural light and store-produced light and adjust their individual intensities accordingly. We would recommend implementing these light-sensor systems on the outside of the complex and in the surrounding streets to stabilize floor lux. This policy would reduce excessive lighting and light pollution by altering public lamp intensity based on external sources of light while maintaining businesses’ freedom to illuminate their storefronts as they choose. We would also advise replacing the current bulbs with more efficient LED counterparts and powering these lamps via solar panels. Overall, we hope that these changes will help make Les Halles a safe and energy-efficient hub.
By Layla Stahr, Michael Wong, Anne-Pia Marty, Jean-Brice Lachaux
 ONDRP (Observatoire Nationale de la Délinquance et des Réponses Pénales)