Retroreflective sheeting

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Flash photo of car with reflective stickers
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Flash photo of moped with retroreflective sheeting tape

Retroreflective sheeting is flexible retroreflective material primarily used to increase the nighttime conspicuity of traffic signs, high-visibility clothing, and other items so they are safely and effectively visible in the light of an approaching driver's headlamps. They are also used as a material to increase the scanning range of barcodes in factory settings. The sheeting consists of retroreflective glass beads, microprisms, or encapsulated lenses sealed onto a fabric or plastic substrate. Many different colors and degrees of reflection intensity are provided by numerous manufacturers for various applications. As with any retroreflector, sheeting glows brightly when there is a small angle between the observer's eye and the light source directed toward the sheeting but appears nonreflective when viewed from other directions.

Contents

Applications

Retroreflective sheeting is widely used in a variety of applications today, after early widespread use on road signs in the 1960s.

High-visibility clothing

High-visibility clothing frequently combines retroreflective sheeting with fluorescent fabrics in order to significantly increase the wearer's visibility from a distance, which in turn reduces the risk of traffic-related accidents. Such clothing is commonly worn as (often mandatory) PPE by professionals who work near road traffic or heavy machinery, often at night or in low-visibility weather conditions, such as construction workers, road workers and emergency service personnel. It is also commonly worn by cyclists or joggers to increase their nighttime visibility to road traffic.

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Reflective leg band in Scanning Electron Microscope, 200x.GIF
Reflective leg band in Scanning Electron Microscope, 15x.GIF
Retroreflective sheeting on high-visibility clothing at varying magnification levels. Clockwise from top left: Yellow safety vest; Retroreflective strip, magnified 8x; Magnified 15x using a scanning electron microscope (SEM); Magnified 200x with SEM.

For road signs

Retroreflective sheeting for road signs is categorized by construction and performance specified by technical standards such as ASTM D4956-11a.; [1] various types give differing levels of retroreflection, effective view angles, and lifespan. [2] Sheeting has replaced button copy as the predominant type of retroreflector used in roadway signs.

There are several grades of retroreflective sheeting which include the three major grades: engineer grade, high intensity prismatic (HIP) and diamond grade. Within these categories are further delineations based on material used and visibility distance. Diamond grade typically has the greatest distance for visibility of the three major categories. [3]

For barcode labels

Barcodes can be printed onto retroreflective sheeting to enable scanning up to 50 feet away. [4]

In motion pictures

The special effects technique of front projection uses retroreflective screens to create false backgrounds for scenes shot in studios. Front projection was used in 2001: A Space Odyssey during the "Dawn of Man" sequence. Other films that have used front projection techniques include Silent Running , Where Eagles Dare and Superman .

Star Wars episodes IV, V and VI used retroreflective sheeting for the lightsaber blades. [5]

Autonomous vehicle navigation

Reflective tape is used to provide an explicit way to do optical navigation of autonomous vehicles. For example, strips of retroreflective tape are used to provide navigation inputs to the prototype Hyperloop pod vehicles on the SpaceX Hypertube test track. [6]

Related Research Articles

<span class="mw-page-title-main">Corner reflector</span> Retroreflector with three orthogonal, intersecting flat surfaces

A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat surfaces, which reflects waves directly towards the source, but translated. The three intersecting surfaces often have square shapes. Radar corner reflectors made of metal are used to reflect radio waves from radar sets. Optical corner reflectors, called corner cubes or cube corners, made of three-sided glass prisms, are used in surveying and laser ranging.

<span class="mw-page-title-main">Retroreflector</span> Device to reflect radiation back to its source

A retroreflector is a device or surface that reflects radiation back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, which does this only if the mirror is exactly perpendicular to the wave front, having a zero angle of incidence. Being directed, the retroflector's reflection is brighter than that of a diffuse reflector. Corner reflectors and cat's eye reflectors are the most used kinds.

<span class="mw-page-title-main">Barcode</span> Optical machine-readable representation of data

A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly referred to as linear or one-dimensional (1D), can be scanned by special optical scanners, called barcode readers, of which there are several types.

<span class="mw-page-title-main">High-visibility clothing</span> Safety clothing

High-visibility clothing, sometimes shortened to hi vis or hi viz, is any clothing worn that is highly luminescent in its natural matt property or a color that is easily discernible from any background. It is most commonly worn on the torso and arm area of the body. Health and safety regulations often require the use of high visibility clothing as it is a form of personal protective equipment. Many colors of high visibility vests are available, with yellow and orange being the most common examples. Colors other than yellow or orange may not provide adequate luminescence for conformity to standards such as ISO 20471.

<span class="mw-page-title-main">Traffic sign</span> Signboard displaying information for road users

Traffic signs or road signs are signs erected at the side of or above roads to give instructions or provide information to road users. The earliest signs were simple wooden or stone milestones. Later, signs with directional arms were introduced, for example the fingerposts in the United Kingdom and their wooden counterparts in Saxony.

<span class="mw-page-title-main">Warning sign</span> Sign that warns people for a risk or danger

A warning sign is a type of sign which indicates a potential hazard, obstacle, or condition requiring special attention. Some are traffic signs that indicate hazards on roads that may not be readily apparent to a driver.

<span class="mw-page-title-main">Stop sign</span> Traffic sign alerting drivers to stop

A stop sign is a traffic sign designed to notify drivers that they must come to a complete stop and make sure the intersection is safely clear of vehicles and pedestrians before continuing past the sign. In many countries, the sign is a red octagon with the word STOP, in either English or the national language of that particular country, displayed in white or yellow. The Vienna Convention on Road Signs and Signals also allows an alternative version: a red circle with a red inverted triangle with either a white or yellow background, and a black or dark blue STOP. Some countries may also use other types, such as Japan's inverted red triangle stop sign. Particular regulations regarding appearance, installation, and compliance with the signs vary by some jurisdictions.

<span class="mw-page-title-main">Traffic cone</span> Cone-shaped marker used for traffic management

Traffic cones, also called pylons, witches' hats, road cones, highway cones, safety cones, caution cones, channelizing devices, construction cones, roadworks cones, or just cones, are usually cone-shaped markers that are placed on roads or footpaths to temporarily redirect traffic in a safe manner. They are often used to create separation or merge lanes during road construction projects or automobile accidents, although heavier, more permanent markers or signs are used if the diversion is to stay in place for a long period of time.

<span class="mw-page-title-main">Bicycle lighting</span> Illumination devices attached to bicycles

Bicycle lighting is illumination attached to bicycles whose purpose above all is, along with reflectors, to improve the visibility of the bicycle and its rider to other road users under circumstances of poor ambient illumination. A secondary purpose is to illuminate reflective materials such as cat's eyes and traffic signs. A third purpose may be to illuminate the roadway so that the rider can see the way ahead. Serving the latter purposes require much more luminous flux and thus more power.

<span class="mw-page-title-main">Raised pavement marker</span> Road safety device

A raised pavement marker is a safety device used on roads. These devices are usually made with plastic, ceramic, thermoplastic paint, glass or occasionally metal, and come in a variety of shapes and colors. Raised reflective markers, such as plastic, ceramic, or metal ones, include a lens or sheeting that enhances their visibility by retroreflecting automotive headlights, while glass road studs gather automotive headlights with a dome shape and reflect the lights with a reflective layer within. Some other names for specific types of raised pavement markers include convex vibration lines, Botts' dots, delineators, cat's eyes, road studs, or road turtles. Sometimes they are simply referred to as "reflectors".

Oilskin is a waterproof cloth used for making garments typically worn by sailors and by others in wet areas. The modern oilskin garment was developed by a New Zealander, Edward Le Roy, in 1898. Le Roy used worn-out sailcloth painted with a mixture of linseed oil and wax to produce a waterproof garment suitable to be worn on deck in foul-weather conditions. Oilskins are part of the range of protective clothing also known as foul-weather gear.

<span class="mw-page-title-main">Projection screen</span> Apparatus for displaying a projected image

A projection screen is an installation consisting of a surface and a support structure used for displaying a projected image for the view of an audience. Projection screens may be permanently installed on a wall, as in a movie theater, mounted to or placed in a ceiling using a rollable projection surface that retracts into a casing, painted on a wall, or portable with tripod or floor rising models as in a conference room or other non-dedicated viewing space. Another popular type of portable screens are inflatable screens for outdoor movie screening.

<span class="mw-page-title-main">Clearview (typeface)</span> Humanist sans-serif typeface

Clearview, also known as Clearview Hwy, is the name of a humanist sans-serif typeface family for guide signs used on roads in the United States, Canada, Indonesia, the Philippines, Israel, Brazil and Sri Lanka. It was developed by independent researchers with the help of the Texas Transportation Institute and the Pennsylvania Transportation Institute, under the supervision of the Federal Highway Administration (FHWA). It was once expected to replace the FHWA typefaces in many applications, although newer studies of its effectiveness have called its benefits into question.

<span class="mw-page-title-main">Safety reflector</span> Safety item that reflects light

A safety reflector is a retroreflector intended for pedestrians, runners, motorized and non-motorized vehicles. A safety reflector is similar to reflective stripes that can be found on safety vests and clothing worn by road workers and rescue workers. They are sometimes erroneously called luminous badges or luminous tags, but this is incorrect as they do not themselves produce light, but only reflect it.

Moisture vapor transmission rate (MVTR), also water vapor transmission rate (WVTR), is a measure of the passage of water vapor through a substance. It is a measure of the permeability for vapor barriers.

<span class="mw-page-title-main">Infrared thermometer</span> Thermometer which infers temperature by measuring infrared energy emission

An infrared thermometer is a thermometer which infers temperature from a portion of the thermal radiation sometimes called black-body radiation emitted by the object being measured. They are sometimes called laser thermometers as a laser is used to help aim the thermometer, or non-contact thermometers or temperature guns, to describe the device's ability to measure temperature from a distance. By knowing the amount of infrared energy emitted by the object and its emissivity, the object's temperature can often be determined within a certain range of its actual temperature. Infrared thermometers are a subset of devices known as "thermal radiation thermometers".

<span class="mw-page-title-main">Sun protective clothing</span> Clothing which blocks light

Sun protective clothing is clothing specifically designed for sun protection and is produced from a fabric rated for its level of ultraviolet (UV) protection. A novel weave structure and denier may produce sun protective properties. In addition, some textiles and fabrics employed in the use of sun protective clothing may be pre-treated with UV-inhibiting ingredients during manufacture to enhance their effectiveness.

<span class="mw-page-title-main">Button copy</span> Method of manufacturing road signs

Button copy is a type of physical design for road signs in the United States. Round plastic retroreflective buttons made of transparent plastic are placed in rows following the contours of sign legend elements, usually painted white, such as letters, numbers, arrows, and borders. In daylight, the buttons visually blend with the white sign legend elements and so are minimally conspicuous. At night, light from each approaching vehicle's headlamps strikes the retroreflective buttons and is reflected back towards the eyes of the vehicle's driver. Thus the sign is made sufficiently conspicuous and legible for adequately fast and accurate recognition and interpretation by drivers.

Retroglo is a reflective yarn designed to increase nighttime safety. It is made of 3M Scotchlite Reflective Material and laminated to a polyester film for added strength. Retroglo is used for a wide variety of applications including high-visibility clothing for joggers, walkers, bicycle riders, and highway workers.

Road traffic control devices are markers, signs and signal devices used to inform, guide and control traffic, including pedestrians, motor vehicle drivers and bicyclists. These devices are usually placed adjacent, over or along the highways, roads, traffic facilities and other public areas that require traffic control.

References

  1. "ASTM D4956 - 19 Standard Specification for Retroreflective Sheeting for Traffic Control". www.astm.org.
  2. "Manual of Traffic Signs - Sign Sheetings". www.trafficsign.us.
  3. "Reflective Sheeting for Signs - Reflective Sheeting Grades and Uses". January 8, 2014.
  4. Retroreflective Labels
  5. Miller, Ron (January 1, 2006). Special Effects: An Introduction to Movie Magic. Twenty-First Century Books. ISBN   9780761329183 via Google Books.
  6. "SpaceX Hyperloop Test-Track Specification" (PDF) (4.0 ed.). SpaceX. 8 January 2016. Archived from the original (PDF) on 15 February 2017. Retrieved 2 February 2016.