Retroreflective Elements Research Articles

Making night-time pedestrians safer using innovative clothing designs

Night-time pedestrians, including recreational walkers and runners, remain at significant risk of being killed or seriously injured, because drivers often fail to see them in time to avoid a collision. Clothing incorporating retro-reflective markers on the moveable joints creates a visual perception of biological motion or “biomotion” which has been shown to improve night-time pedestrian conspicuity. This study investigated whether clothing with markings in the biomotion configuration retains its conspicuity if adapted to include thinner or patterned retro-reflective strips making it more acceptable to wear for recreational pedestrians. In a night-time closed road study, the relative conspicuity of pedestrians to 14 young drivers with normal vision (mean age 24.3 ± 3.1 years) was assessed for pedestrians wearing different thicknesses and patterns of biomotion strips and compared with typical clothing worn by night-time pedestrians, including commercially available sports clothing with retro-reflective elements, a fluorescent yellow top, and black clothing. Results showed that all the biomotion configurations resulted in significantly longer recognition distances: around 2 times longer than the sports clothing, 2.5 times longer than the fluorescent top and 4 times longer than the black clothing. Similar trends were found for the distance at which drivers correctly identified pedestrian orientation (towards or sideways to the vehicle), with significantly longer distances for all the biomotion configurations, when compared to the sports, fluorescent top and black clothing. These findings highlight the effectiveness of biomotion clothing, even when using retro-reflective strips as thin as 0.75 cm and have implications for clothing designs for recreational walkers and runners to enhance their night-time safety.

ВСТАВКИ РОЗМІЧАЛЬНІ ДОРОЖНІ. ІСТОРІЯ ВИНИКНЕННЯ. ТЕХНІЧНИЙ АНАЛІЗ ТА РОЛЬ У БЕЗПЕЦІ ДОРОЖНЬОГО РУХУ

Road studs is dotted devices with retroreflective elements or internal light sources fixed or embedded in the pavement of carriage way and / or on the roadside and by light signals warn, inform or guide road users in conditions of insufficient lighting. Road studs are intended for improving the visual orientation of drivers at dark time of the day and in adverse weather conditions on the highways, streets and roads of settlements. According to statistics, about 50% of all traffic accidents and accidents with fatalities and / or injuries occur on the highways in the dark time (night, morning and evening twilights). First road studs occurred on the roads in 1947. The inventor, Percy Shaw, had patented the device and opened his own factory for its production. After that their mass production, improvement and distribution worldwide, including Ukraine started. After the analysis of road studs usage in different countries, a new edition of GOST was developed, which allow considering in detail the location, requirements for color, installation methods, forms of the road studs, etc. According to foreign experts, the retro reflectivity is important for visual orientation in the dark time and has a positive impact on the traffic safety. Usage of retroreflective elements on the highways will increase the visibility of path of movement and stationary objects, which will significantly improve the safety of road users. Keywords: road studs, retroreflective elements, road safety, road accidents, highway.

Incidental acoustic retroreflection from building façades: Three instances in Berkeley, Sydney and Hong Kong

This study investigates acoustic reflection from three building façades, each of which forms an array of corner cube retroreflectors. The façade of Latimer Hall (Berkeley, USA) has deep rectangular balconies that typically provide 56 simultaneously visible retroreflective elements; the Ainsworth Building (Sydney, Australia) has a sawtooth façade with 95 simultaneously visible corner cubes; and a façade of the Murray Building (Hong Kong) has 280 simultaneously visible recessed retroreflective windows. Acoustic measurements using a collocated loudspeaker and microphone are used to observe the retroreflection at two positions on each site. Results show a cluster of reflections corresponding to the façade, which stand out from the general reflection pattern, especially at high frequencies. Measured reflected energy levels are greater than geometric predictions, especially at low frequencies, while finite-difference time-domain simulation of one of the sites yields results closer to the measurements. This study sheds light on a distinctive, but not rare, façade acoustic reflection phenomenon, which can play a role in understanding urban acoustic issues, and also may find application in other areas of architectural acoustics where reflection of sound back to the source would be beneficial.

ПИТАННЯ ПІДВИЩЕННЯ БЕЗПЕКИ РУХУ ЗА РАХУНОК ВИКОРИСТАННЯ НОВИХ СВІТЛОПОВЕРТАЛЬНИХ ЕЛЕМЕНТІВ

The article presents the results of the development, production and implementation of modern high- tech products - micro-prism retroreflective elements for the arrangement of roundabouts of motorways, street and road networks in order to improve traffic safety at night. KEY WORDS: LIGHT-ROTATING ELEMENT, MICROPRISMATIC STRUCTURE, MATRIX­ORIGINAL.

Measurement of optical characteristics of catadioptric retroreflectors

A technique for determining the effective scattering area of retroreflective catadioptric (reflective–refractive) devices is presented. An experimental setup for measuring the effective scattering area and comparative calculated and measurement data on the effect of fabrication errors on the characteristics of retroreflective elements are presented.

PEDESTRIAN SAFETY, IN PARTICULAR SCHOOL-AGE CHILDREN, DURING THEIR MOVEMENT AT NIGHTTIME

The issue of the safety of pedestrians, in particular school-age children during their movement at nighttime is considered with the coverage of such aspects of road safety as road infrastructure, vehicle design, behavior of drivers and pedestrians, especially children directly as the most vulnerable road users, and educational activities. Particular attention is paid to the fact that road traffic is the most complex and difficult aspect of the environment that a child can experience, especially during in poor daylight and in darkness (because in the autumn and winter it gets dark very early and time when children should go to school or from school falls at this period of the day). In the paper is shown how the visibility zones for drivers of motor vehicles in the darkness and in bad weather conditions are changing. Also, in the paper is provided information about the visibility of pedestrians who use or do not use on the clothes the retro-reflective elements, at the use of dipped and distant headlights of the car. The legislation of Ukraine and European countries in this area, which in particular regulates the requirements for the use of retro-reflective elements, as well as the practice and recommendations regarding their use, are analyzed. At the same time, the paper conducted a review of existing decisions that ensure pedestrian safety and allow them to be more visible to drivers of motor vehicles, especially with the onset of dusk and at nighttime. The analysis of the recommendations contained in the Consolidated Resolution on Road Traffic (R.E.1) concerning the increase of road safety in the dark time of day is carried out. Recommendations on possible actions to enhance the safety of pedestrians at the national level, including school-age children during their movement at nighttime are given. Keywords: road safety, road traffic accident, vulnerable road user, pedestrian, vehicle, retro-reflective element.

Development and Implementation of High-performance Circular Retroreflective Elements for Illumination of Highways and Transport Networks of Kyiv

Development and Implementation of High-performance Circular Retroreflective Elements for Illumination of Highways and Transport Networks of Kyiv

Розробка та впровадження високоефективних кругових світлоповертальних елементів для автомагістралей та транспортних мереж Києва

Розробка та впровадження високоефективних кругових світлоповертальних елементів для автомагістралей та транспортних мереж Києва

Electroluminescent Materials Can Further Enhance the Nighttime Conspicuity of Pedestrians Wearing Retroreflective Materials.

We investigated the nighttime conspicuity benefits of adding electroluminescent (EL) panels to pedestrian clothing that contains retroreflective elements. Researchers have repeatedly documented that pedestrians are too often not sufficiently conspicuous to drivers at night and that retroreflective materials can enhance the conspicuity of pedestrians. However, because retroreflective elements in clothing are effective only when they are illuminated by the headlamps of an approaching driver, they are not useful for pedestrians who are positioned outside the beam pattern of an approaching vehicle's headlamps. Electroluminescent materials-flexible luminous panels that can be attached to clothing-have the potential to be well suited for these conditions. Using an open-road course at night, we compared the distances at which observers responded to pedestrians who were positioned at one of three lateral positions (relative to the vehicle's path) wearing one of two high-visibility garments. The garment that included both EL and retroreflective materials yielded longer response distances than the retroreflective-only garment. This effect was particularly strong when the test pedestrian was positioned farthest outside of the area illuminated by headlamps. These findings suggest that EL materials can further enhance the conspicuity of pedestrians who are wearing retroreflective materials. EL materials can be applied to garments. They may be especially valuable to enhance the conspicuity of roadway workers, emergency responders, and traffic control officers.

Avaliação retrorrefletiva de pintura de demarcação horizontal: peculiaridades e considerações sobre a norma e os requisitos mínimos nacionais

<p>A retrorrefletividade das pinturas de demarcações horizontais permite a visibilidade da sinalização viária durante a noite, impactando diretamente a segurança da via. O Brasil emprega normas e requisitos mínimos internacionas que foram parcialmente adaptados para as condições do país. De maneira geral, tais adaptações reduziram os níveis de segurança exigidos por estes importantes dispositivos, fato que pode acarretar prejuízos à condição de segurança e conforto. A partir da avaliação ao longo de dois anos de três segmentos experimentais, um rodoviário e dois urbanos, com diferentes tipos de demarcações e materiais, buscou-se fazer uma análise crítica da pertinência da forma de avaliação normativa no Brasil, bem como estudar o impacto da chuva, do acúmulo de sujeira e da geometria dos retrorrefletômetros sobre o desempenho da sinalização horizontal. Como esperado, demarcações empregando material termoplástico apresentaram um desempenho superior àquelas com tinta acrílica. O efeito abrasivo da interação pneu-pavimento desgasta tais dispositivos, reduzindo o número de elementos retrorrefletivos (microesferas); entretanto, a combinação tráfego mais precipitação mostrou-se positiva por permitir a limpeza “natural” da sinalização. Para o trecho urbano, o efeito da sujeira foi tão prejudicial quanto à abrasão causada por veículos pesados. A análise da retrorrefletividade, obtida com diferentes geometrias, perante limites mínimos nacionais e internacionais, demonstrou que os índices mínimos de retrorrefletividade aplicados no Brasil são pouco exigentes, merecendo, portanto, serem rediscutidos para melhor atender aos quesitos de segurança viária.</p>

APPLICATION AND CHARACTERISTICS OF WATERBORNE ROAD MARKING PAINT

Horizontal road markings are one of the essential safety features of modern roadways. All of the utilised systems consist of a pigmented coating containing partially embedded retroreflective elements such as glass beads. In addition to durability and functionality of the road marking, ease of application and effect on human health and environment are primary considerations for their selection. Road marking systems can be divided into plural component materials that cure due to chemical reaction occurring at the site of application, thermoplastics that require heat for application, and paints, drying upon evaporation of the dissolving medium. The focus of this paper is on road marking paints with a special emphasis on contemporary waterborne materials. Over 100 years old solventborne technology furnishes paints that afford consistent application properties under a variety of conditions such as lower temperatures and high humidity. Their environmental and human health impact is significant and durability quite poor. Modern waterborne paints are based on acrylic resins and incorporate developed in the 1990s quick-set chemical mechanism for drying. Under favourable weather conditions, they dry faster as compared to solventborne. However, their known weakness is risk of washout in case of rain and sluggish development of washout resistance at marginal application conditions like high humidity and low temperature. Impact of waterborne paints on human health and environment is very significantly minimised as compared to other materials. Their durability is significantly higher as compared to solvent-based paints. Analysis of characteristics of waterborne road marking paints and preliminary results from their trial application in Croatia are presented herein. Based on the presented comparison with solventborne materials, after results from test application become available, intelligent decisions regarding future use of waterborne road marking paints in Croatia and other countries that have not embraced this technology shall be possible.

MEMS Retro-Phase-Modulator for Free-Space Coherent Optical Communications

This paper describes an electrostatically actuated microelectromechanical systems (MEMS) device combined with small-scale retroreflective elements to produce a hybrid MEMS retro-phase-modulator suitable for use in a retroreflective free-space coherent optical communications system. In contrast to other MEMS retromodulators reported, which have concentrated on intensity modulation, the device reported in this paper produces an optical phase modulation. Two types of retroreflective elements, namely, a ball lens and an off-the-shelf retroreflective strip have been incorporated into the modulator. This paper reports a transmission system operating at higher bit rates than those that were previously published for similar schemes. Modulation has been achieved at 400 bits/s with a transmission cost of 80 pJ/bit

Microelectromechanical systems actuated small-scale retroreflectors for free space optical communications

This paper describes an electrothermal MEMS actuation device combined with small-scale retroreflective elements to produce a modulator suitable for use in a retroreflective optical free space communications system. The advantages and disadvantages of different retroreflective elements are compared, the steady state conditions of the device are investigated to give an understanding of operation, and the dynamics of the structure are investigated and compared when loaded with various retroreflective elements and when unloaded. Dynamic modelling and testing indicates practical operating frequencies extending to a few kilohertz.

Fiber-end interferometric sensor using cooperative retroreflectors

The well-known fiber Doppler velocimeter is examined as a high-resolution sensor of small displacements. The system is greatly improved through the use of thin-film retroreflective elements on the moving object. Range and sensitivity are increased, and problems in obtaining optical alignment become trivial. The interferometer is used here to study the flight dynamics of an electromagnetic constitutes a more general sensor coupling arrangement. actuator, although the fiber-retroreflector combination constitutes a more general sensor coupling arrangement.