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Highly retroreflective horizontal road markings: drivers' preception
Abstract
Horizontal road markings are common safety features that can be found on all roads. Scientific analyses demonstrated that road safety was improved on roads where the markings had higher retroreflectivity. The standard retroreflectivity reaches only about 350 mcd/m²/lx initially and is permitted to drop to 100 mcd/m²/lx. On a 2 km stretch of a curved rural road, we have applied markings with improved retroreflectivity, approaching 700 mcd/m²/lx initially. Whereas durability of the system is still under evaluation, opinion of drivers about the increased retroreflectivity was assessed using a questionnaire.
Amongst 156 valid filled questionnaires, 58-75% of respondents reported noticing markings with retroreflectivity higher than the standard with those who use the road every day most likely to observe this added safety feature. Over 80% of respondents felt that road safety during nighttime driving would increase if horizontal markings had higher retroreflectivity. Amongst the responders, there was an overrepresentation of young drivers and underrepresentation of older ones, which might have skewed the results.
... Based on professional expertise and observations, majority of existing inadequacies of the quality of road markings in Poland are associated with improper selection of materials, the lack of supervision, and the prevailing policy of rewarding in tenders the lowest bid price the combination of these factors is a strategy that can be described as designed-to-fail: there is no motivation whatsoever for the road marking contractors to maximise the quality, so only the cheapest materials that are available on the spot market are utilised, with the hope that the applied road markings would somehow pass the minimum requirement. In a series of articles originating from our research, it was repeatedly shown that the use of high-end materials for road markings would not only prolong their service life Burghardt et al., 2019), but also enhance the retroreflectivity for driver comfort (Horberry et al., 2016;Diamandouros and Gatscha, 2016;Pashkevich et al., 2017) and increased road safety (Avelar and Carlson, 2014). Very importantly, it was calculated that from long-term perspective the use of such materials would not cause increase in the total price (Burghardt and Pashkevich, 2020). ...
Correct signage belongs to critical factors affecting road traffic safety. During a naturalistic driving study in Poland major mistakes associated with signage were noticed and analysed: road works were announced and speed limits were reduced from 120 km/h to 70−80 km/h, but no road construction could be found. Measurements of drivers’ speed showed their complete disregard of the limitations: average speed of light vehicles remained at 113 km/h and lorries at 88 km/h. Assessment of the encountered 683 road signs revealed 12.5% of them to be inadequate (10.9% falsely informed drivers). Evaluation of contrast ratio of road markings (their replacement was the claimed reason for road work) showed low values both before and after re-placement (Weber contrast 0.6). It is hypothesised that erroneous road signage and its contradiction with the visible road features are contributing to the permanent disobedience of traffic rules in Poland and are decreasing road safety.
... Amongst reported benefits of maintaining high R L and thus maximising the visibility of RM in vehicles' headlights at night, one must list statistical analyses that have correlated the increase in R L with a decrease in accident rate (Avelar and Carlson, 2014;Carlson et al., 2015). RM with high R L were also reported as making driving easier and were generally positively perceived by drivers (Horberry et al., 2006;Diamandouros and Gatscha, 2016;Pashkevich et al., 2017). In addition, inadequate quality of RM was indicated as hampering the emerging technologies of advanced driver assistance systems and automated vehicles, which rely on machine vision (Burghardt et al., , 2021b. ...
Road markings are road elements that require frequent periodic renewals (not replacement) to maintain their key properties. To evaluate the impact of materials selection on sustainability of road markings, several representative products were tested in the field. The results revealed that the main impactor for their service life was selection of paint, followed by the choice of glass beads. The measured length of service life was used to calculate the consumption of resources for a series of renewals until end-of-life. The outcome clearly demonstrated that lowest carbon footprint was achieved with road marking materials that afforded longest service life, even if their composition was not environmentally friendly. The methodology described in this article may be used by road administrators and by scientists as a tool for quick assessment of sustainability of road markings based on their service life during homologation testing and composition of the utilised materials.
... It was reported that increase in retroreflectivity of RM at least partially helps in overcoming the obstacle of low CR under any conditions (Burghardt et al. 2021a). Such increase was not only positively perceived by drivers (Diamandouros & Gatscha 2016, Horberry et al. 2006, Pashkevich et al. 2017, but also correlated with decreased number of accidents (Avelar & Carlson 2014). To accomplish it, one could to reach for novel, high-end RM systemscombination of high-end paints and 'premium' glass beads were described by us several times, in various configurations: in all of the cases the performance was enhanced in terms of retroreflectivity and in addition prolonged service life was achieved (Burghardt 2018, Burghardt et al. 2016, 2021b, 2021c. ...
Road markings are critical road safety features for both human drivers and for machine vision technology used in advanced driver assistance systems and in the emerging technology of automated vehicles. Amongst the parameters, contrast ratio is necessary for appropriate recognition of road markings. To assess the contrast ratio of road markings at various roads, still images of roadway were obtained from a dashboard camcorder used for a naturalistic driving study in Poland. Road markings and neighbouring roadway surface were measured for luminance and Weber contrast was calculated. At the studied representative roads average contrast ratio was 0.8 under daytime illumination and 2.0 at night; enhancement of the contrast through digital image manipulation resulted in increases to 2.3 and 6.8, respectively. Under poor visibility daytime conditions (interference from glare or rain), average contrast ratio dropped to 0.5 (enhanced 1.4); in the worst case it was below 0.1. Consequently, the current machine vision technology could fail under some poor visibility circumstances. The image enhancement indicated that both the initial and digitally enhanced contrast ratios were important.
... Appropriate upkeep of RM, renewal before the top layer of GB is lost, is seen, based on the results presented herein and the professional knowledge, as the simplest and most effective method of very significantly reducing the contribution of RM to MP. In addition, adequately maintained RMwith high R L -make driving easier (Horberry et al., 2006;Pashkevich et al., 2017), improve mobility of elderly population (Charlton et al., 2006;Payyanadan et al., 2018), and increase road safety (Avelar and Carlson, 2014;Diependaele, 2019). RM are the least durable elements of road safety infrastructure, which emphasises the need for the use of solutions that provide extended service life: a viable option would be employment of high-end materials capable of furnishing not only high initial R L , but also capable of maintaining it, which implies that the base layer would remain covered with GB Burghardt et al., 2021Burghardt et al., , 2021a. ...
Road markings are often listed amongst meaningful contributors to pollution with microplastics. However, the reported estimates do not address the renewal frequency and its association with the key parameter of road markings – retroreflectivity. This parameter, achieved because of a layer of glass beads on the road markings surface, fails before the plastic-bearing layer could be abraded. Field and laboratory assessment indicated the presence of several layers of paint and glass beads, confirming that the road markings were renewed before abrasion could occur. A methodology to employ luminance histograms to estimate loss of road markings was developed and used to approximate the emissions at selected exemplary locations. The estimates indicated that road marking loss at the most used areas of pedestrian crossings was below 6%, which is much less than previously reported. Thus, the emissions of microplastics of any dimension from this source were calculated to be between 0.1 and 4.3 g/person/year (except in Nordic countries, where 56.3 g/person/year could be reached). Consequently, road markings do not appear to be as significant source of microplastic pollution as was reported before, except for specific local considerations.
... It was consistently reported that premium-quality road marking materials (both the paint and the glass beads) can furnish adequate R L for longer periods than standard products [21,56,57]. Road markings with high R L are positively perceived by drivers [58][59][60]; they were also associated with lower accident rate [16]. The strong correlation between the MV response and R L emphasises the need of appropriate maintenance of road markingsnot only for human drivers, but also for MV [11,12,61]. ...
The same features of road markings – retroreflectivity and daytime visibility – are the key parameters for their recognition by both human drivers and for machine vision (MV) utilised by the emerging technology of automated vehicles. For the purpose of side-by-side performance assessment of various road marking types, 8 materials, differing in colour and retroreflectivity, were tested under laboratory conditions for visibility by LiDAR and by camera under different weather conditions. Visibility was evaluated under various intensities of rain and fog; simulated effects of glare from oncoming vehicle were also tested. The response of MV equipment depended on (1) the equipment itself, (2) retroreflectivity of road marking, (3) their structure, (3) their colour, and (4) the utilised glass beads. Overall, the highest MV intensities were measured with structured cold plastic reflectorised with ‘premium’ glass beads (refractive index 1.6–1.7) and with white road marking tape. Poorest outcome gave greyish paint imitating severely worn markings and orange paint. Under the conditions of wetness and fog, use of the ‘premium’ glass beads resulted in significantly improved camera contrast ratio, but there was no such correlation with LiDAR intensity. On average, introduction of moisture lowered the measured contrast ratio by 80 % (range 69 %–86 %) and LiDAR response intensity by 84 % (range 72 %–96 %). Results from this case study can be used for development of road marking materials with improved recognition by MV.
... Since market penetration of road markings with very high RL is low, lacking are analyses related to its influence on road safety, on fatigue and comfort of drivers, and other associated effects. Based on survey results showing that drivers notice high RL Pashkevich et al., 2017) and the reported lesser drivers' stress on wellmarked roads Diamandouros and Gatscha, 2016), meaningful positive effects can be anticipated. An eye tracking experiment done in the field has shown that horizontal road markings are perceived by drivers at the level of gazes, with minimal focus (Pashkevich et al., 2018); their observation depends on the distance from intersection, which agrees with previous simulator reports related to field of view needed for proper steering of a vehicle (Land and Lee, 1995). ...
Horizontal road markings are inalienable feature on almost all roads because their presence results in significant increase in safety for all road users. By providing delineation, they help drivers in keeping the vehicle in the traffic lane. At night time, retroreflectivity (RL) of road markings, achieved by incorporating glass beads on the marking surface, is perceived by the drivers and its level was reported to be associated with lower accident rate. Indeed, usable life of road markings is measured by their RL. It is shown herein, based on field tests, that for thick-layer structured road marking systems the selection of glass beads has profound effect not only on retroreflectivity, but also on durability. Exemplary financial analysis demonstrates that despite higher one-time expense, savings can be realised in the long-term with the use of premium materials. Moreover, the same high quality and high RL of horizontal road markings that are needed for human drivers are demanded by machine vision algorithms, which provides guidance in the emerging autonomous vehicles technology. Therefore, maintaining of horizontal road markings at high level is necessary-until all of the vehicles would be self-driving, and very possibly even afterwards. Furthermore, because of reasonable price and broad availability, durable horizontal road markings have a potential of being one of the solutions to lower accident occurrences in poorly developed countries.
Road markings are a necessary safety feature on almost all roads. For appropriate performance they must be reflectorised with glass beads. To demonstrate the differences between traditional and modern thin-layer road marking solutions, four road marking systems were compared in the field. Based on measurements of retroreflectivity, influence of glass beads and paint on service life was estimated. The use of high-performance waterborne paint reflectorised with premium glass beads permitted for over sixfold extension of durability. Financial analysis demonstrated that the considerable additional expense associated with purchase of modern materials was fully offset through increased service life: even 65% savings could be realised in the long term. Subsequent analysis of the used glass beads under optical and scanning electron microscopes provided information about their surface; intact and damaged glass beads were observed. Surprisingly, damaged glass beads were found to have crater-like surface features instead of the expected scratches.
Road markings are a necessary safety feature that guides drivers. For visibility in darkness, when accident risk and severity are the highest, road markings must be reflectorised with glass beads to be visible when vehicle headlights shine on them. Renewal of thick-layer structured road markings that have lost retroreflectivity but have retained the structure mostly intact is performed through application of thin-layer paint coatings. Based on a field experiment, it was demonstrated that selection of premium glass beads profoundly extends the durability of the renewed markings, which could be further enhanced through the use of high-performance waterborne paint. Whereas the standard system based on solventborne paint and typically used glass beads failed after a single winter, the use of premium road marking system at least doubled the service life. The extended road marking service life translates to 50% savings in material consumption, 50-97% lower emissions of volatile organic compounds, and a decrease in long-term financial expense by 5-26%.
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