Download or read book Development of Measures to Improve Field Performance of Retroreflective Raised Pavement Markers written by Yunlong Zhang and published by . This book was released on 2009 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using Finite Element Analysis of Retroreflective Raised Pavement Markers to Recommend Testing Procedures for Simulating Their Field Performance written by Ravi Prakash Agrawal and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Retroreflective Raised Pavement Markers (RRPMs) supplement other pavement markings to provide guidance to road users. Previous research concerning durability of the RRPMs suggests that their performance has been degrading over the years. One of the main causes for underperformance of the RRPMs is the lack of appropriate laboratory testing standards that can test the adequacy of the RRPMs to perform in field conditions. There is a need to modify the existing standards or develop new testing procedures that can better simulate field conditions. This requires identifying critical locations and magnitudes of stresses inside the markers during the tire-marker impacts that happen on roads. The goal of this research was to identify critical magnitudes and locations of the stresses in RRPMs during the tire-marker impacts by doing the finite element modeling and simulation of the impacts, and use the information to recommend laboratory testing procedures that could simulate real-world conditions. The researcher modeled and simulated the tire-marker impacts using the finite element tools Hypermesh and LS-DYNA. He calibrated the material properties of the marker models to improve the tire-marker model. Based on the tire-marker impact simulations, the researcher concluded that the critical compressive stresses during impacts are located at the edge contacts of retroreflective sides with the top surface. The critical stresses may also occur at lower and upper corners of the marker. The other areas, especially the lower half of the marker, had tensile stresses. Angle of impact was found to be a critical external variable that affected the stresses inside the markers and the marker-pavement interface forces. The researcher then modeled and simulated a few laboratory-testing procedures that could simulate the field performance of the RRPMs. Based on these simulations, the researcher recommended that the ASTM compression test for evaluation of RRPMs be continued or a similar test be developed. He suggested development of one new test (named as offset compression test) that could better replicate the field conditions. He also recommended having a review of the ASTM flexural test.

Download or read book Using Finite Element Structural Analysis to Study Retroreflective Raised Pavement Markers written by Jiaxin Tong and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the stress inside Retroreflective Raised Pavement Markers (RRPMs) under tire-marker impact and laboratory testing scenarios. Many RRPMs have poor durability although they meet certain standards of the existing laboratory tests. It has been suspected that the current testing procedures might not be adequate to decide the field performance of RRPMs. Thus, it is necessary to evaluate the existing laboratory testing procedures and develop additional ones that could simulate the field performance of RRPMs more accurately. The tire-marker impact on rigid and flexible pavement will be investigated to identify the critical locations and magnitudes of stress inside markers during the impact. Various external factors, such as tire loading, tire speed, contact angle and contact location, might have effects on the stress inside markers during the impact and be considered as critical factors when developing a laboratory test. On the other hand, RRPMs have different profiles in terms of height, lens slope, and size etc, which affect the structure and field performance as well. The study explores the stress inside markers during the impact by varying the external factors and marker profile. In addition, the interface forces between RRPMs and pavement surface will be studied. Furthermore, the tire-marker impact simulation on rigid and flexible pavement will be compared so that specific testing procedures can be distinguished based on pavement type. Finally, the existing laboratory tests will be examined and additional tests be recommended based on the tire-marker impact analysis. The researcher found that the critical compressive stress is produced at the top edges of the markers on both types of pavement, while the patterns of critical tensile stress can be different between the two types of pavement. In addition, tire loading and contact location were determined to have effect on the stress inside the markers. Furthermore, different loading rates should be used in laboratory test based on pavement type. Finally, the researcher evaluated four laboratory tests and found that each test has its merit but none of them can test RRPMs comprehensively, so it is recommended that the four tests are used together to test RRPMs.

Download or read book Durable Retroreflective Pavement Markings and Markers Increase Visibility for Drivers in Wet Night Conditions written by Misty A. Boos and published by . This book was released on 2009 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing retroreflectivity of markings during rainy, foggy, nighttime conditions is a major challenge. Research has shown that pavement markings reduce crashes at night on dry pavement, but not at night on wet pavement. (Migletz, 2002 pg. 6) Because of the need to improve visibility for drivers under adverse conditions, recent research (2000 to the present) has been targeted toward understanding visibility needs and developing minimum retroreflectivity specifications for different driver groups under different environmental conditions. Research on this topic has been compiled in this RSB in section II: "Wet Night Visibility of Pavement Markings." Increased retroreflectivity performance in wet, night conditions may help to reduce fatalities, but ensuring and defining this improved performance includes a particular set of challenges. For example, "Pavement marking retroreflectivity under wet pavement conditions averaged only 46% of the comparable values under dry pavement conditions. For example, to achieve a wet pavement retroreflectivity of 150 mcd/m2/lux, the marking would need a dry-pavement retroreflectivity of 326 mcd/m2/lux." (Migletz, 2002 pg. 2) Challenges to improving retroreflectivity performance mentioned in recent research include: Type of material and installation methods; Service life, durability and cost of durable materials; Damage to materials by forces such as weather and traffic wear; Setting minimum reflectivity standards (as cited in the MUTCD 2003 and/or by state DOTs); Developing strategies and tools to measure retroreflectivity; Marking and marker installation issues including increasing shortages of skilled workers for installation and maintenance; Location of installation, climate and traffic load on roadway; Funding and standards for maintenance; Many new technologies entering the market, each requiring evaluation; Environmental regulations; Product acceptance and approval; Driver needs (including differing needs based on driver age and time of day); Vehicle type and the visibility concerns of trucks vs. cars. The durability and service life of retroreflective materials is of particular concern because the service life of some pavement markings and markers can be very short (as little as 6 months in some cases). When these markings fail or their reflectivity is reduced drivers experience difficulty seeing the road. (Migletz, 2002). The following organizations have explored the durability or service-life of pavement markers and markings. Their work can be found in section I: "Durability of Retroreflective Pavement Markings, Markers": Texas Transportation Institute (TTI); Virginia Transportation Research Council (VTRC); Federal Highway Administration (FHWA); New Jersey DOT; Alabama DOT; Oregon DOT; Florida DOT; Georgia DOT; Indiana DOT; American Society of Civil Engineers; ARRB Group Ltd. The following organizations have proposed research into retroreflectivity or wet, nighttime driving conditions. Their proposals can be found in this RSB Section III: "Research in Progress": Oregon State University; Iowa State University; Mississippi State University; North Dakota DOT; Pennsylvania DOT. When durable, retroreflective pavement markings are properly selected for a site and installed and maintained correctly they can help drivers navigate in wet night conditions and they have the potential to decrease traffic fatalities. Research, listed in the following pages, provides an overview of current work, but much exploration remains to be done on this complex issue.

Download or read book Wet Night Visibility of Pavement Markings written by Ronald Bruce Gibbons and published by . This book was released on 2004 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes an investigation into the performance of pavement markings in wet night conditions. The performance of a typical pavement marking will degrade when it gets wet. This is a result of the flooding of the marking optics, thereby reducing retroreflectivity. Several technologies are available to improve wet marking performance. In this project, six technologies were tested using both standard measurement methods and participant evaluations. The results show that two of the marking technologies, raised retroreflective markers and wet retroreflective tape, outperformed the group under all conditions. These markings were also highly accepted by the participants. The results also show that the standard paint and glass beads technology is the worst performing and the least desirable of those evaluated. A comparison of the ASTM retroreflectivity measurement methods and the measured luminance results also indicates that the methods are suitable for the conditions used in the evaluation; however, possible additions and corrections to the methods are outlined in this report. A follow-up study is underway to allow development of a performance-based specification for pavement markings for wet night visibility.

Download or read book Evaluation of the Performance of Permanent Pavement Markings and Retro Reflectors in Snowplowable Raised Pavement Markers written by Neville A. Parker and published by . This book was released on 2002 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation and Modeling of Pavement Marking Characteristics Based on Laboratory and Field Data written by Maged M. Mohamed and published by . This book was released on 2019 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drivers rely on the visibility of pavement markings to maintain a safe road path especially during nighttime and challenging weather conditions. With the growing demand for pavement marking materials, durability and long-term weatherability of these products is critical. Current performance evaluation methodology using field test-deck protocols requires significant time and resources, and under these protocols the performance of a pavement marking can be monitored for a period of up to three years. In addition, safety-related issues such as exposing technical staff to road hazards while applying the marking materials and collecting measurements, along with road closure consequences, are of concern. The primary goals of this research were to develop an accelerated laboratory-based procedure that could evaluate the performance of pavement markings, overcome the shortcomings of current evaluation practice, and investigate the safety performance of pavement markings based on existing crash data and results from a driver simulation study. For the laboratory-based procedure, a three-wheel polisher device (TWPD) and xenon arc chamber (XAC) were employed to replicate varying traffic, snowplowing, and weather conditions. The deterioration of the physical measurements (i.e., dry and wet retroreflectivity, color change, and durability) of waterborne and thermoplastic markings was modeled. All of the performance measures logarithmically deteriorated under different TWPD loadings, except for the durability of the thermoplastic markings which followed a linear degradation function. A significant reduction in percent retroreflectivity was observed in the initial part of the TWPD testing but leveled out as the number of cycles increased. This deterioration pattern is similar to what occurs in the field, as retroreflectivity dramatically decreases after the first few months of installation and then stabilizes before the end of its service life. On the other hand, a linear increase in retroreflectivity and color change occurred during the artificial weathering exposure time (i.e. 2,000 hours) due to the change in surface physical properties. The color analysis revealed an important relationship between pavement marking retroreflectivity and color change. After traffic loading, all colors darkened due to the exposure of the black asphaltic color or the abrasion of the upper layer of marking, and in turn retroreflected less light while different color change patterns were experienced under the artificial weathering. The color analysis results showed that when a color closely resembles white, the sample retroreflected more light. The TWPD and weatherometer effectively simulated and accelerated the operational and environmental effects (e.g., traffic, snowplowing, sunlight, moisture, and temperature) so that assessment of pavement marking performance could be completed in an abbreviated time frame. The results yielded a significant relationship between all performance measures assessed in both the laboratory and field. Evaluating the performance of pavement marking products using an accelerated laboratory-based procedure provides a department of transportation (DOT) with a flexible tool to cope with the rapidly evolving industry through the establishment of guidelines that might be used for the selection and maintenance of the pavement markings. This procedure can be used to compare different marking materials and assess marking materials whether they bear severe traffic operating conditions or harsh climates before implementation in short period of time. To assess the safety performance of pavement markings, specifically on two-way, two-lane rural roads which are common in the state of Idaho, two separate approaches were adopted. First, a crash analysis study over eight years (2010-2017) on rural roads in Idaho was conducted to understand the relationship between retroreflectivity deterioration of edgelines and crash occurrence. Field retroreflectivity data for waterborne edgeline markings from thirty-eight sites were collected and modeled over twelve months across six districts with different environmental conditions. The results yielded a logarithmic relationship between retroreflectivity and age, and pavement markings in districts subjected to higher ground snow loads deteriorated faster than those with lower ground snow loads. This faster deterioration trend in northern districts was attributed to winter maintenance activities and harsh weather. Even though, a clear statistical pattern was determined for District 1, which was subjected to the higher ground snow loads among all districts, the methodology used in this study could not definitively conclude that crash rate increased with lower edgeline retroreflectivity. Second, a study using the University of Idaho's driving simulator was implemented to evaluate the safety effects of different edgeline pavement marking widths (e.g., 4-inch and 6-inch) and deteriorations (e.g., 0%, 25%, 50%, and 75% deterioration) on driver behavior. The results indicated that statistically significant differences were observed during nighttime conditions when comparing the driver's lane deviation (vehicle's lateral position) between the wider 6-inch longitudinal edgeline pavement markings and standard 4-inch edgeline marking. Drivers consistently maintained a lane position that slightly favored the edgeline side when exposed to a 4-inch marking and increasingly shifted away from the centerline as edgeline deterioration worsened. The results of the statistical analysis implied that 4-inch markings and severely deteriorated pavement markings cause higher variation values in driver lateral position which in turn could affect overall driver safety. This research benefits transportation agencies, particularly those sited in cold-weather regions, by enabling them to predict the deterioration of marking materials and assist in the scheduling of maintenance marking projects to maximize the operational and safety benefits of the existing material. This research also make recommendations with regard to a minimum retroreflectivity threshold that should be maintained for pavement markings of two-way, two-lane rural roads and the use of wide pavement markings.

Download or read book Pavement Marking Materials written by Anthony L. Andrady and published by Transportation Research Board. This book was released on 1997 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Retroreflective Raised Pavement Markers written by Gerald L. Ullman and published by . This book was released on 1994 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geometric Optimization of Retroreflective Raised Pavement Markers written by Lukai Guo and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As the field service life of retroreflective raised pavement marker (RRPM) is much shorter than expected, it is necessary to identify the causes and thus improve the RRPM structural design to mitigate the main failure modes, such as poor retention from pavements, structural damage, and loss of retroreflectivity. One strategy for extending RRPM service life is to enhance RRPM geometric characteristics to decrease critical stresses in markers. The main purpose of this thesis is to analyze the relationship between stresses, failure modes, and RRPM profiles. Based on this research, some measures are suggested in order to avoid corresponding failure modes by optimizing RRPM profiles.

Download or read book Retroreflective Raised Pavement Marker Field Testing written by Gerald L. Ullman and published by . This book was released on 1994 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of Pavement Markings for Improved Visibility During Wet Night Conditions written by Benjamin H. Cottrell and published by . This book was released on 1996 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study evaluated the night visibility of waffle tape and paint with large beads, particularly during wet night conditions. Data were collected at two sites along a primary arterial. The evaluation included an examination of (1) the application of the markings, (2) the visibility of the markings using retroreflectometer measurements and subjective assessments, and (3) the costeffectiveness of the markings. The study revealed: (1) compared with paint with standard beads, the waffle tape and paint with large beads were slightly more retroreflective during light rain at night and recovered quicker after flooding out, (2) the marginal improvement in visibility during periods of light rain do not offset the operational problems of applying paint with large beads, and (3) the benefits of waffle tape during light rain do not appear to justify its use solely for wet night visibility. Because of the above findings, snowplowable raised pavement markers, which are very visible in wet night conditions, appear to be more cost-effective. The study recommends that (1) VDOT continue to use and maimain snowplowable raised pavement markers for visibility during wet night conditions, (2) VDOT continue to monitor FHWA's study on all weather pavement markings, and (3) the Suffolk District consider testing nonsnowplowable raised pavement markers to assess their use as a low-cost alternative to improve visibility during wet night conditions where snowplowing occurs infrequently.

Download or read book Retroreflective Raised Pavement Marker Field Testing written by Gerald L. Ullman and published by . This book was released on 1994 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Improved Pavement Marking Materials written by John M. Dale and published by . This book was released on 1967 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory tests and field studies were conducted on the performance characteristics of conventional pavement marking materials currently in use. A discussion was presented of their shortcomings and studies conducted on the physical nature of reflective materials, with particular emphasis on performance characteristics under various types of water films. A new pavement marking was designed and tested with encouraging results. A systematic approach for the design of a pavement marking system has been developed wherein one qualifies the surface to be marked, determines the water film thickness to be encountered, and then selects one of the several marking systems that will perform under the imposed conditions.

Download or read book Retroreflective Raised Pavement Marker Field Testing written by Gerald L. Ullman and published by . This book was released on 1992 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Department of Transportation and Related Agencies Appropriations for 2002 written by United States. Congress. House. Committee on Appropriations. Subcommittee on Dept. of Transportation and Related Agencies Appropriations and published by . This book was released on 2001 with total page 1036 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effectiveness and Criteria for Placement of Raised Pavement Markers Synthesis Study written by Yi Jiang and published by . This book was released on 2006-06-15 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Raised pavement markers (RPM) are used in highway centerlines and edge lines as a traffic safety measure to provide more positive guidance for motorists in inclement weather and low light conditions. They are applied by highway agencies as delineation treatments to improve driver preview distances. The Indiana Department of Transportation has installed RPMs on selected roadway sections primarily as position guidance devices in order to better guide drivers in night conditions. In Indiana, RPMs are installed on all interstate highways and multilane divided highways. However, RPMs are used on only a few of the Indiana's two-lane highways. It was found that two-lane rural roads in Indiana experience relatively large number of fatal crashes. Thus, INDOT engineers would like to know if the safety on rural roads can be improved by placing RPMs on more two-lane highways. They would like to find out how effective the installed RPMs are in improving the safety of the motoring public. If the RPMs are effective, what criteria should be applied to identify the roadway sections and curves for RPM installations to improve safety? To address these questions and concerns, this synthesis study was conducted to search answers from the published literature and to identify and summarize the effectiveness of RPMs and the criteria for RPM placement. The objectives of this study were (1) to locate and assemble documented information on RPM applications; (2) to learn what practice has been used in other states for RPM applications; (3) to organize, evaluate, and document the useful information that is acquired; and (4) to provide recommendations on RPM applications based on the evaluated information. Currently, there is not a uniform guideline among state highway agencies for RPM placements on different types of highways. Some states install RPMs non-selectively on all state-maintained highways. Other states select roadways for RPM installations solely on the basis of traffic volumes or on the basis of several parameters, including roadway type, traffic volume, safety record, and horizontal curves. Moreover, RPM replacement cycles vary from state to state. Through this study, the information on RPM effectiveness was located, assembled, reviewed, and documented.