3 M Ratro Reflection

8/4/2019 3 M Ratro Reflection

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Traffic Safety TimesT TS

March 2009

InsideNew Product

Event based Commonwealth Youth Games & Beijing Olympics

Importance of

Praveen Sood

Median Marker

City Signing

Observation Angle

Guest Column

www.3m.com/tss

3M Median Markerhe traffic scenario on city roads and highways has been changing

very fast due to increased number of vehicles, plying at muchThigher speeds on wider roads.

The National and State Highways in India are undergoing a rapid

transformation from 2 lane to 4, 6 and multi lanes to cater to the

growing transportation requirements of people and goods.

The rapid expansion of metros and other big cities resulted in meteoric

rise in vehicular population, many times higher than the traffic-carrying

capacities of the roads, in these cities.

The total vehicle population has almost doubled from 37 million to 71

million in last 8 years.

However, with the road and safety infrastructure not keeping apace, the

total number of fatalities in road accidents has increased by nearly

100% (from 64000 in 1995 to 120,000 in 2008) in last 13 years.

edians are constructed all along these roads to segregate

and smoothen the flow of traffic in the respective directions

on both city and highway roads.MHowever, it is very common to find sharp curves, broken or

protruding median edges, pedestrians and vehicles crossing over the

medians, pot holes, shrubs and plants projecting on to the lane next

to the median on these roads.

With much higher average vehicular speed on highways and bumper

to bumper traffic in peak hours on city roads, it has become

extremely difficult for the motorist to quickly capture what's lying

ahead on the road, process the information and take the required

action, all in a very short span of time.Added to these, extremely dark ambient conditions during nights,

insufficient and poor lighting distribution from vehicular headlights

and blinding light from vehicles in opposite direction, make it even

more difficult to quickly adapt to the median and road condition

ahead.

W h y i s M e d i a n

Visibility Important?

As such, 'median visibility' has become a vital

and critical factor for vehicular and motor is t sa fe ty,

especially during nights and inclement weather conditions.

3M Median MarkerThe 3M Median Marker is a

highly durable retro-reflective

product, which provideshighest visibility to the critical

median edge making it easier

for the motorist to quickly

capture the median and road

condition ahead.

It helps the motorist have

sufficient clarity and time to take required action incase of any

unforeseen obstruction and hence contributes to reduced accidents

and enhanced safety of motorists and vehicles.

With its extremely tough, vandal-proof, dirt-resistant and excellent

retro-reflective characteristics, it is proving to be a boon to vehicles and

motorists in both cities and highways throughout India.


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March 2009

Page 1March 2009

Event Based SigningTraffic signs are the only means of communication with the

motorists and pedestrians on a road. They caution, warn and

inform the users about the changing road geometry, various laws

and about the location or road names. They help in smooth

movement of traffic and in finding ways for tourists and business

travelers. With increasing population of vehicles and road users,

the importance of traffic signs have increased manifold.

Whenever a city hosts any special event like a religious fests,sports event, political rallies, musical shows etc, a lot of people

travel to that city from various other cities and countries. In such a

scenario the requirement for traffic signage further increases. Of

late the concept of event based signing solution has come up.

Event based Signing Solution serves two important purposes.

These are

1) Providing proper guidance to the people thereby

maintaining traffic efficiency even when the population

of the city increases many times

2) To create awareness about the event

Many countries have used event based signing for Internationalsports events. Most recent one is the Beijing Olympics in China

and Commonwealth Youth games, India.

Beijing Olympics

Special Traffic signs were

installed with Olympics

games logo. Most advanced

reflective sheeting was used

to make the sign visible and

legible.

We can put pics here


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March 2009

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Commonweal thGames 2010 Anupdate on signage

Commonwealth

Youth Gamesctober 2008, Pune city hosted Commonwealth Youth

games. To equip the city with proper infrastructure, Pune

Municipal Corporation decided to upgrade the existingOtraffic signs with the new signs made with the most advanced

reflective sheeting. Customised designs were developed for the

signs to make the city proud of hosting such a big event.

eeping pace

w i t h t h eKworld, Indiais going to host

Commonwea l th

Games 2010 in

Delhi. The event

will attract many

tourist from various

parts of the world

a l o n g w i t hparticipating sports

persons. In order to

ensure smooth

traffic movement

and safety of both

m o t o r i s t s a n d

pedestrians, delhi

government has

decided to upgrade

the traffic signs

wi th the most

a d v a n c e dreflective sheeting. All the 3 authorities viz, NDMC, PWD & MCD

have developed the plan and have already started inviting bids

for the work.


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March 2009

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Importance of Observation Angle Performance for

Retro-reflective Sheetings

material's retroreflectivity is dependent upon what is known as the

material's angularity. For prismatic materials, angularity can beAdescribed using the observation angle and entrance angle.The measure of the separation of a driver from his/her headlights is

represented by the observation angle. Observation angle is the angle

formed when light leaves its source, hits a sign face, and returns to the

observer's eye position. The observation angle is fairly small in familysedans and sports cars; bigger in SUVs, pick-up trucks and minivans; and

much larger in large trucks where the driver's eye position is often six feet

above the headlamps.

No matter what the situation, every motorist on the approach to a sign will

experience a 0.2, 0.5, 1.0, 1.5, and possibly a 2.0 - degree observation

angle depending on the type of vehicle being driven1. Observation angles

get larger every second as we drive towards any retro-reflective traffic

control device, including signs. This fact plus the changing vehicle mix

trend toward larger vehicles, SUVs and pickup trucks, with larger

comparative observation angles, caused the agencies across the world to

direct users and specifies toward sign sheetings that work more efficiently2

at higher observation angles.

Incident light on the retroreflective surface is retro-reflected in a conicshape. A perfect retro-reflector would send the light back to the

headlight. That would be useless to the nighttime driver. Thus, some part of

the light needs to be diverged from the incoming direction and return

somewhere around the headlight where the driver is likely to be.

Different sheeting materials distribute the retroreflected light differently. In

fact , some retroref lect ive

materials scatter some of the

incoming light in directions that is

not useful to the driver, thus

r e d u c i n g t h e o v e r a l l

retroreflective efficiency. If a

particular material redirects the

otherwise scattered light to the

driver eye, that material serves

the driver better.

The sign brightness observed by the driver is greatly affected by the

location of the driver with respect to his/her headlights. The manner in

which light is sent back to a driver is critical as to what that driver sees.

Performance of retroreflective sheetings can differ greatly. Most

retroreflector also have diffuse reflection. Diffuse reflected light is

simply wasted, as it does not help the nighttime driver. Higherefficiency sheetings divert more of this otherwise wasted light toward

the driver.

The cone of returned light is not uniform within the cone. There is

typically more light returned toward the headlight and less light is

returned as one moves away from his/her headlights (upward), such as

a heavy vehicle driver. The distribution of light within the cone depends

on the retroreflective properties of the material.

The performance of retroreflective sheetings can be evaluated in two

benchmarks: 1) What percent of light is being retroreflected, and 2)

how is that retroreflected light percentage distributed within the cone3

of retroreflection?The difference between sheetings is evident in the amount and manner

in which light is sent back to a driver. The sheeting retroreflects light in

the general but opposite direction of the incoming headlight. The driver

can be vertically close to his/her headlights and therefore has small

observation angle (such as in a passenger sedan or a sports car), or

have a larger separation and therefore a larger observation angle (such

as a heavy vehicle).

The percentage of retroreflected light depends on the general optical

properties of the sheeting. If the sheeting returns more light to smaller

observation angles, it is at an expense of the larger observation angles.

If more is returned to larger observation angles, less remains for

smaller observation angles. For instance, if a sheeting is 30% efficient,

and if this sheeting returns 20% of light to 0.50 or smaller observation

angles, the remaining 10% is returned to observation angles larger

than 0.50. If the percentage of light returned to 0.50. and above is

increased to 15%, the portion that is returned to lower observation

angles will have to be 15%. The total will be 30% at all times.

The only way to ensure adequate return to all relevant

observation angles without a need for additional sign illumination is to

increase the overall light return efficiency. Increasing light return

efficiency in significant scale requires a notable change in the optical

design of the sheeting. This is why technology like full cube corner with

optical efficiency of 100%, address the needs of as many drivers aspossiblethe 85th percentile driver, not the 50th percentile driver in any

given vehicle, especially larger vehicles such as heavy vehicles and

RVs.

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