3 M Pavement Markings 3 M Wet Reflective

3 M Pavement Markings Agenda § The need for Wet Reflective Pavement Markings §

3 M Pavement Markings know the challenges of driving at night – in the

ncreased Traffic Safety Risks in Rainy Conditions 3 M Pavement Markings “…drivers are three

3 M Pavement Markings 5 © 3 M 2009. All Rights Reserved.

3 M Pavement Markings Retroreflectivity Efficient Glass Bead Technology Light enters the bead ….

$3 M Pavement Markings Defining Refraction? § Refraction – bending of light as it$

3 M Pavement Markings Have you noticed how an object seems to “bend” in

$3 M Pavement Markings Refractive Index is a measure of the degree of bending.$

$3 M Pavement Markings How does refractive index relate to pavement markings? 10 ©$

The bead actsisas a lensfor andretroreflection. focuses light. 3 M Pavement But. Markings pigment

The index bead actually bends the light much! 3 M Pavement Markings The 1.

3 M Pavement Markings But what happens when we add water? 13 © 3

Water distorts the lens. Light must bend more to hit the target. The 2.

3 M Pavement Markings For performance in all weather, one type of bead can’t

3 M Pavement Markings Introducing the 3 M All Weather Dual Optics System §

3 M Pavement Markings ASTM (American Society for Testing and Materials) Test Methods §

3 M Pavement Markings ASTM E 2177 Conditions of Wetness Measure dry Wet the

3 M Pavement Markings ASTM E 2176 Continuous Wetting Measure dry 19 Continually wet

3 M Pavement Markings ASTM E 2832 Continuous Wetting Equipment 20 Continually wet the

3 M Pavement Markings Test Method Comparisons for Sample Pavement Markings NEW Product Dry

3 M Pavement Markings Test Method Comparisons for All Weather Liquids NEW Element Series

3 M Pavement Markings Wet Reflective Pavement Markings in Action § Pavement Marking Video

3 M Pavement Markings Thank you! 24 © 3 M 2009. All Rights Reserved.

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3 M Pavement Markings Agenda § The need for Wet Reflective Pavement Markings § NEW 3 M Microcrystalline High Index Optics Technology § ASTM Methods of Measuring Wet Retro Reflectivity § Video of Wet Reflective Pavement Markings § Open Discussion and Questions 2 © 3 M 2009. All Rights Reserved.

3 M Pavement Markings know the challenges of driving at night – in the § Rain hitting the windshield § Movement & conditions of the wipers § Steamed windshield § Glare from oncoming cars § Headlight misalignment § Road spray § Light transmission through the rain 3 © 3 M 2009. All Rights Reserved.

ncreased Traffic Safety Risks in Rainy Conditions 3 M Pavement Markings “…drivers are three times as likely to be involved in an accident during rainy or wet pavement conditions… Source: Development of Human Factors Guidelines FHWA-RD-99 -130 December, 1999, Page 6 4 Brodsky & Hakkert (1988) Accident Analysis and Prevention, 20(3) 161 -176 © 3 M 2009. All Rights Reserved.

$3 M Pavement Markings Defining Refraction? § Refraction – bending of light as it$

3 M Pavement Markings Defining Refraction? § Refraction – bending of light as it passes from one substance to another. Here, the light ray passes from air to glass and back to air. The bending is caused by the difference in density of the two substances. 7 © 3 M 2009. All Rights Reserved.

$3 M Pavement Markings Refractive Index is a measure of the degree of bending.$

3 M Pavement Markings Refractive Index is a measure of the degree of bending. Incoming light in air RI=1. 00 The Diamonds good news: sparkle because they have a very high refractive index. But unfortunately they’re not 3 M has developed microcrystalline ceramics with too practical for use inindex! pavement markings…. a very high refractive 2. 4 RI=2. 4 I=ic era. Rm d c n e o in m ll ia ta D s ry Microc Cubic zirconia RI=2. 1 Higher in Gla dex bea ds RI= 1. 8 -1. 9 ss 9 © 3 M 2009. All Rights Reserved. RI= 1. 5

$3 M Pavement Markings How does refractive index relate to pavement markings? 10 ©$

The index bead actually bends the light much! 3 M Pavement Markings The 1. 92. 4 index bead best directs the light in drytoo conditions 1. 5 index bead 2. 4 index bead 12 1. 9 index bead © 3 M 2009. All Rights Reserved.

Water distorts the lens. Light must bend more to hit the target. The 2. 4 index bead best directs the light in wet conditions. 3 M Pavement Markings 1. 9 index bead 2. 4 index bead 14 © 3 M 2009. All Rights Reserved.

3 M Pavement Markings For performance in all weather, one type of bead can’t do it all! Dry conditions i Optimal Refractive Index (RI) = 1. 8 - 1. 9 15 © 3 M 2009. All Rights Reserved. Wet conditions i Optimal Refractive Index (RI) = 2. 4 - 2. 5

3 M Pavement Markings Introducing the 3 M All Weather Dual Optics System § Dry reflective beads (RI = 1. 9) provide maximum reflectivity under dry conditions § Wet reflective beads (RI = 2. 4) incorporate water into the optics, providing maximum reflectivity when wet. § They work together to provide higher levels of performance in all weather conditions 16 © 3 M 2009. All Rights Reserved.

3 M Pavement Markings ASTM (American Society for Testing and Materials) Test Methods § ASTM E 1710 (dry reflectivity) § ASTM E 2177 (wet recovery) - Wetting with water sprayer - Measure after 45 seconds § ASTM E 2176 (wet continuous) - High rain fall rate - Specified water sprayer § ASTM E 2832 (new wet continuous) - Low rain fall rate - Specified water sprayer, water pump, wind shield - To be measured after 14 days on the road 17 © 3 M 2012. All Rights Reserved.

3 M Pavement Markings ASTM E 2177 Conditions of Wetness Measure dry Wet the marking This test measures pavement markings when damp, or simulates testing immediately after a rainstorm 18 Allow to drain for 45 sec Measure again

3 M Pavement Markings ASTM E 2176 Continuous Wetting Measure dry 19 Continually wet the marking & take reading until they reach steady state. This test simulates measurement under rain conditions. It best differentiates true wet reflective performance.

3 M Pavement Markings ASTM E 2832 Continuous Wetting Equipment 20 Continually wet the marking & take reading until they reach steady state. This test simulates measurement under rain conditions. It has a lower rain rate and different

3 M Pavement Markings Test Method Comparisons for Sample Pavement Markings NEW Product Dry Reflectivity E 2176 Wet Continuous E 2832 Wet Continuous E 2177 Wet Recovery 380 AW 750 mcd 350 mcd 450 mcd 500 mcd 710 750 mcd 350 mcd 400 mcd 500 mcd 21 © 3 M 2012. All Rights Reserved.

3 M Pavement Markings Test Method Comparisons for All Weather Liquids NEW Element Series E 2176 Dry Wet Reflectivity Continuous E 2832 Wet Continuous E 2177 Wet Recovery Dry Only 1600 mcd 75 mcd 100 mcd 175 mcd Series 50 900 mcd 125 mcd 200 mcd 345 mcd Series 90 500 mcd 180 mcd 325 mcd 500 mcd 22 © 3 M 2012. All Rights Reserved.

3 M Pavement Markings Wet Reflective Pavement Markings in Action § Pavement Marking Video from Florida § Pavement Marking Video from Pennsylvania Turnpike § Flash light demonstration § Open Discussion and Questions 23 © 3 M 2009. All Rights Reserved.