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Utilization of Current Technologies to Capture Sign and Pavement Marking Retroreflectivity

Utilization of Current Technologies to Capture Sign and Pavement Marking Retroreflectivity. Sign MUTCD Retroreflectivity Compliance Dates.

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Utilization of Current Technologies to Capture Sign and Pavement Marking Retroreflectivity

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  1. Utilization of Current Technologiesto Capture Sign and Pavement Marking Retroreflectivity

  2. Sign MUTCD Retroreflectivity Compliance Dates • January 2012 June 2014 – Implementation and continued use of an assessment or management method that is designed to maintain traffic regulatory and warning sign retroreflectivity at or above the established minimum levels • January 2015 - Replace identified regulatory, warning, ground-mounted guide signs (except street-name) • January 2018 - Replace identified street name & overhead guide signs • May 14, 2012 • Eliminated 46 items • Revised 4 others items • Safety related compliance dates maintained (8) • Revision #2 of the 2009 MUTCD

  3. Requirements of a Traffic Sign • Visible to the driver • adequate levels of retroreflectivity and luminance (amount of light received by driver) • Nighttime more critical than daytime fatalities

  4. MUTCDMaintenance and Inspection Methods Visual nighttime inspection Measured sign retroreflectivity Expected sign life Blanket replacement Control signs Others The use of the state of the art in cameras, illumination and computer vision allow a new assessment method based into an objective and repetitive measure, carried on in an automatic way, of the traffic signs in their actual context.

  5. Technology

  6. Components of Retroreflectivity • luminance cd/m2 (candela/m2) • Illuminance = lx (lux) REFLECTED LIGHT (LUMINANCE) α INCIDENT LIGHT (ILLUMINANCE) luminance illuminance Retroreflectivity (RA = = cd/lx/m2) @20α (observation angle)

  7. Luminance Measurement High sensitivity cameras installed on board measures the luminance, even under low light conditions The response curve of the cameras is equivalent to the human eye, and allows to measure luminance consistently

  8. Illuminance Control A specific lighting system, computer regulated and calibrated Provides a highly repetitive measurement. Non-glaring for road users

  9. Calculated Illumination Dual cameras and computer algorithms eliminate ambient light sources leaving a controlled and known illuminance value LEDs + van headlights Van headlights - Luminance reflected from only the LED headlight (illuminance known) = minus

  10. Geometry Cameras sensors are geometrically calibrated to measure distances and dimensions in the scene Together with the multiple sensors on board measure the geometry context of the retroreflectivity measurement

  11. Sign Quality as Perceived by Operator AMAC data is based on the actual performance of the traffic sign as seen by the driver at night

  12. Data Characteristics • Retroreflectivity (background and legend) for all colors of post-mounted-signs and overhead structures • Sign luminance • Contrast Ratio for warning signs (legend / background) • Sign size, height above the roadway • MUTCD code • Evaluation from the driver eye perspective • Traffic sign inventory with GPS positional data • Optimizes traffic signs maintenance by providing quantitative retro values

  13. Accuracy Testing • All tests preformed at TTI(Texas Transportation Institute -Texas A&M University) • Performance Criteria • Static Closed-Course • Dynamic Closed-Course • Dynamic Open-Road • Evaluation of background and legend retroreflectivity measurements

  14. Dynamic Open-Road Testing • 12-mile route • Rural divided high speed highway • Undivided highway • Low speed urban roadways • With and without roadway lighting

  15. Dynamic Open-Road Results: Background

  16. Repeatability

  17. Advantages of Mobile Platform • Cost effective • Measures sign from drivers perspective • No traffic control necessary • Safety – no workers in active traffic • Actual sign retro measurements to be used in degradation analysis • Complete data capture for engineering analysis

  18. Mobile Pavement Marking Retroreflectivity

  19. Multiple Line Data Capture utilizes digital image processing

  20. Pavement Markings Retroreflectivity Data Capture • The AMAC system utilizes the onboard image processing system to capture pavement marking retroreflectivity.  • This includes striping, and pavement graphics.  • The system measures retroreflectivity values as well as dimensions for all markings within and adjacent to the lane of travel.

  21. AMAC For further information on AMAC visit our website at www.amacglobal.com Toll Free: 855.DBi.AMAC (855.324.2622) Email: info@amacglobal.com

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