Improve Skid Resistance Research Articles

RESTORATION OF SURFACE PROPERTIES OF CONCRETE PAVEMENTS: OVERVIEW OF PRACTICES AND ASSESSMENT IN FRANCE

This article presents an overview of practices and assessment in France regarding the restoration of surface properties of concrete pavements, focusing on enhancing skid resistance, safety, and durability while minimizing environmental disturbances. The evolving priorities in highway pavement management underscore the importance of integrating aesthetic, urbanistic, and functional considerations, including stormwater management and noise reduction. The article outlines a new circular under preparation in France aimed at improving skid resistance through mechanical processes, emphasizing the qualitative aspects of pavement surface treatment over quantitative metrics. It discusses the significance of microtexture and macrotexture in achieving desirable skid resistance, detailing the specifications for aggregates to ensure durability and resistance to polishing. The article also highlights various surface treatment techniques, including surface dressings, sawn grooving, and peening, based on over 15 years of French experience. These techniques are evaluated for their effectiveness in restoring skid resistance on heavily trafficked pavements, with a special focus on transverse grooving and its impact on water drainage and pavement drying. The comprehensive approach to pavement restoration presented in this article reflects a broader commitment to road safety, environmental considerations, and the overall performance of highway networks. (Abstract generated by AI tool ChatGPT 4)

Road Surface Texture Evaluation and Relation to Low-Speed Skid Resistance for Different Types of Mixtures

Pavement skid resistance is significant for driving safety. British Pendulum Number (BPN) is commonly used as a low-speed skid resistance indicator, whereas sometimes it is impractical for data collection on roads in service. Since skid resistance is greatly affected by pavement surface texture, this research aims to evaluate pavement surface texture comprehensively and estimate the low-speed friction BPN from road surface texture on macro- and micro- scale. Asphalt Concrete (AC) and Stone Mastic Asphalt (SMA) were included. Road surface texture was evaluated from four aspects, texture depth, amplitude-related Root Means Square (RMS), elevation variances corresponding to different wavebands and texture spectral analysis. Texture depth indicators include Mean Texture Depth (MTD) and Mean Profile Depth (MPD). Elevation variances with three wavebands, from 5 mm to 50 mm, from 0.5 mm to 5 mm and from 0.024 mm to 0.5 mm respectively, were obtained. The results show that MPD is well correlated with MTD. Elevation variances with different wavebands demonstrates that the elevation variance of macro-texture with long wavelengths from 5 mm to 50 mm dominates the total variance. Spectral analysis shows that texture level is larger when the wavelength is beyond 4 mm, which is consistent with elevation variances. A linear regression between BPN and single texture index, as well as multiple linear regression analysis were conducted. The former regression result indicates that it is not feasible to estimate BPN using single index due to low correlation coefficient R2. The latter shows that the BPN can be estimated from texture levels corresponding to 64 mm and 2 mm, and the micro-texture. The R2 can be up to 0.684. This research will contribute to fast acquisition of BPN from pavement surface texture, thus improving skid resistance.

Effect of High Polymer, Crumb Rubber, and Epoxy-Modified Asphalt Binders on Laboratory Performance of Open-Graded Friction Course Mixtures

Open-graded friction course (OGFC) is a thin asphalt mixture surface layer. It is gap-graded with a high percentage of coarse aggregates that are nearly uniform in size, resulting in a high percentage of interconnected air voids and asphalt binder, which provides improved skid resistance, visibility, and decreased pavement–tire noise. However, construction personnel at the Louisiana Department of Transportation and Development reported that conventional OGFC mixtures have durability issues and shorter service life, compared with thin asphalt mixture lifts. Hence, effects of different asphalt binder types on the performance of OGFC mixtures were evaluated. Five types of asphalt binder were utilized: conventional styrene-butadiene-styrene (SBS) asphalt binder PG 76-22M; high SBS content asphalt binder PG 88-28; diluted epoxy asphalt (EA) binder with two different dosages (25% and 50%); and a hybrid modified asphalt binder prepared with SBS and crumb rubber modifier PG 76-22G. The optimal aggregate structures were determined based on minimum required air voids and voids in coarse aggregate. Physical and mechanical tests were conducted to assess the performance of OGFC mixtures, including draindown, permeability, loaded wheel track, and Cantabro abrasion loss. Results indicate that OGFC mixtures incorporating diluted EA binder exhibited lower draindown values than mixtures containing PG 76-22M and PG 88-28. Moreover, mixtures with PG 88-28 and 50% EA binders demonstrated improved resistance to rutting. Mixtures with 50% EA and PG 88-28 binders demonstrated improved durability, compared with mixtures with PG 76-22M for unaged and aged conditioning, as measured by Cantabro abrasion loss values.

ECONOMIC FEASIBILITY AND ENVIRONMENTAL IMPLICATIONS OF PERMEABLE PAVEMENT IN PALESTINE

Permeable pavement is considered one of the sustainable management options for roadway networks, which mitigates a number of problems associated with stormwater, ground water pollution, and traffic safety. In this study, the economic feasibility, vehicle operation, and environmental implications of implementing permeable pavement in Nablus, Palestine have been determined by selecting the local roadways that satisfy the permeable pavement requirement, such as low traffic volume, grade less than 5%, speed limit up to 50 km/h, and subgrade with good permeability. The total costs of construction and maintenance for both conventional asphalt and permeable pavement have also been compared based on the life cycle cost analysis (LCCA). Finally, the environmental implications such as the expected increase in the amount of ground water and the reduction in water pollutants have been investigated. The results of the analysis show that the permeable pavement is applicable for the local roadways that have satisfied the requirements, which are 61 roadways. Furthermore, it could lead to an annual significant increase in ground water by 107,404.7 m3 and slightly reduce the cost of construction and maintenance by up to 1,912,000 ILS during its life period compared to conventional asphalt pavement. Moreover, applying porous asphalt could enhance vehicular traffic safety by improving skid resistance.

Optimization of Anti-Skid and Noise Reduction Performance of Cement Concrete Pavement with Different Grooved and Dragged Textures

Cement concrete pavements are crucial to urban infrastructure, significantly influencing road safety and environmental sustainability with their anti-skid and noise reduction properties. However, while texturing techniques like transverse grooving have been widely adopted to enhance skid resistance, they may inadvertently increase road noise. This study addressed the critical need to optimize pavement textures to balance improved skid resistance with noise reduction. Tests were conducted to assess the influence of surface texture on skid resistance and noise, exploring the relationship between texture attributes and their performance in these areas. The investigation examined the effects of texture representation methods, mean profile depth, and the high-speed sideway force coefficient (SFC) on noise intensity and pavement skid resistance. The findings revealed that transverse grooves significantly improved the SFC, enhancing skid resistance. In contrast, longitudinal burlap drag, through its micro- and macro-texture adjustments, effectively reduced vibration frequencies between the tire and pavement, thus mitigating noise. Utilizing the TOPSIS multi-objective optimization framework, an optimization model for pavement textures was developed to augment skid resistance and noise reduction at varying speeds. The results indicated that at 60 km/h, an optimal balance of groove width, depth, and spacing yielded superior skid resistance with a minimal noise increase. At 80 km/h, increased groove spacing and depth were shown to effectively decrease noise while maintaining efficient water evacuation. The optimal pavement texture design must consider the specific context, including traffic volume, vehicle types, and operating speeds. This study provides essential guidance for optimizing urban cement concrete pavement textures, aiming to diminish traffic noise and bolster road safety.

Evaluation of the Effect of De-icing Chemicals on Performance of Airport Concrete Pavement under Freeze-Thaw Cycles

Weather conditions such as rainfall and freeze-thaw cycles affect the pavement performance of airports; therefore, methods such as using de-icing chemicals are considered in order to maintain the normal condition of the airport runway. In addition to the above factors, de-icing chemicals play an important role in pavement performance and the damage caused to it due to their chemical nature. Therefore, investigating the effect of de-icing chemicals and determining the appropriate material to maintain the airport's pavement is a priority for engineers. In this study, the effect of three de-icing chemicals, sodium chloride, potassium acetate, and ethylene glycol (at concentrations of 23.3%, 49%, and 69.07%, respectively) on skid resistance (The British Pendulum Test (BPT) and The Road Test Machine (RTM)) and the mechanical properties (Compressive Strength Test) of the concrete under Freezing and Thawing Cycle were investigated. The BPT test results showed that sodium chloride resulted in better skid resistance than other chemicals when the number of cycles is more than 100 cycles. This result was also obtained for all cycles in the RTM test. Also, ethylene glycol was not suitable for improving skid resistance based on BPT and RTM tests. Furthermore, the results of the compressive strength of concrete mixtures showed that the de-icing chemicals reduced the compressive strength of concrete mixtures. Based on all the results, sodium chloride had better results than other chemicals.

Using bauxite as alternative for coarse aggregate in asphalt mixture: Improving skid resistance

The depletion of natural resources promotes to search for alternative of virgin pavement materials with the aim of ensuring the performance of pavement especially skid resistance, which is often linked to financial and health services of the country. To solve the issues, the paper attempts to employ bauxite as alternative for coarse aggregate of surface layer to improve skid resistance. To this end, the performance of calcined bauxite aggregate was characterized on the basis of some laboratory tests. Thereafter, radar chart method was used to evaluate the comprehensive skid resistance of different aggregates, followed by preparing asphalt mixture based on optimization results. Currently, the skid resistance of asphalt mixture composed of different aggregate was examined by the three-wheel polishing device (TWPD) combined with dynamic friction tester (DFT). After the process, the multiple linear regression model was performed considering the morphological, mineral and chemical characteristics of aggregate with the aim of predicting the long-term skid resistance. As for physical and mechanical properties, the different grades of calcined bauxites show an increase about 20%∼200% compared with limestone. From the radar chart method, it was observed that calcined bauxite, especially 88# calcined bauxite, was found to exist highest comprehensive skid resistance. It is obvious that the model involving mineral and chemical properties is able to exist higher accuracy, adjusted R2 having values even exceed 0.9. In addition, it was found that the cost-benefit of 88# calcined bauxite and 75# calcined bauxite were 22.82 and 12.70 respectively. Herein, the study allows us a feasible approach to ensure the demand of pavement and mitigate the challenge for environment.

Laboratory Experimental Studies on Previews Concrete Pavements

Abstract: Pervious concretes are sp ecial type of concrete gaining attention because of their environmental benefits. These are concretes generally having 15 to 35% voids and they are considered as eco friendly materials. The strengths of the pervious concrete are lower than conventional concrete due to their higher porosity. They are generally made up of coarse aggregates, cement and without or with small amount of fine aggregates. They are considered as sustainable material it has may environmental benefits like storm water management, ground eater recharge, mitigation the urban heat island effects, many traffic related benefits such as noise reduction improving skid resistance etc. These are generally adopted in low traffic areas such as foot paths, parking lots etc. because of their lower strength. Being an eco friendly materials research researches are carried to improve the strength so that they can be used for pavement.

Comparison Of Winter Maintenance Requirements (Estonia, Latvia, Lithuania)

Three Baltic states are located next to each other on the coast of the Baltic Sea. Similarly, to Finland, density of population in these countries is low. All three countries have large amount of state roads with low traffic intensity.Climatic differences are minimal. Milder climate is in coastal area but inland the weather conditions are more severe. The average air temperature in January in Estonia is from -2 to -7 degrees Celsius but in Lithuania from -1 to -5 degrees Celsius. The number of snowy days fluctuates from 50 to 120.All three countries have common contracts for summer and winter maintenance where the responsibility for maintenance activities lays on the contractors. Despite common history the methods of the assignment of road maintenance contracts are different in every country. Estonia awards contracts in open tenders and has performance-based contracts. Latvia has the contract awarded to the State Joint Stock Company «Latvijas autoceļu uzturētājs» (“Latvian Road Maintainer”) by law and the contract is unit price based. Lithuania has the contract awarded to the state-owned company « Kelių priežiūra» the contract is performance-based.The requirements for road conditions are quite similar in all three countries. They have three levels of maintenance.High service level means snow and ice-free surface of the road pavement during winter in constant weather conditions and quick response in case of worsening road conditions.Medium service level means that snow and ice is allowed on the surface, but activities must be undertaken to improve skid resistance. The lowest service level means that snow and ice is allowed on the surface and activities to improve skid resistance (mostly only snow cleaning) may be undertaken in some spots only.In Estonia the expenses for winter maintenance are lower than in the neighbouring countries but it does not have impact on traffic safety during winter.

Effect of aggregate properties on asphalt pavement friction based on random forest analysis

Pavement friction largely depends on surface texture characteristics, which are directly related to the corresponding aggregate properties. This study selected forty-five field pavement sites, which were constructed using seven typical types of aggregates available from eleven different quarries in Oklahoma, as the testing beds. Aggregate properties were characterized in the laboratory using the Aggregate Imaging System (AIMS), and pavement texture and friction data were collected in parallel in the field using a three-dimensional laser imaging system and Grip Tester. The traditional multivariate friction models were developed while several regression coefficients did not follow engineering judgment. Subsequently, the random forest analysis (RFA) was performed to evaluate the pavement surface friction subject to various aggregate properties. Loss of texture (%) is identified as the most significant aggregate characteristic for friction evaluation, accounting for 26.54% contribution to pavement surface friction. Traffic volume and temperature also exhibit significant impacts, with 31%, 14.7% contributions to pavement surface friction, respectively. This study is beneficial to better understand the effect of aggregate properties on pavement friction and to improve skid resistance performance in the field.

Life-Extending Benefit of Chip Sealing for Pavement Preservation

Chip seals are effective pavement preservation treatments that are usually applied to address non-fatigue cracking, weathering, and raveling, to seal the surface, to delay oxidation, and, finally, to improve skid resistance. This study used field performance data of test sections from the Pavement Preservation Group Study being conducted by the National Center for Asphalt Technology and the Minnesota DOT’s Road Research Facility. Data from test sections located in a low-traffic-volume road with a hot, wet, no-freeze climate collected over a period of 7 years were used to evaluate the effect of several chip seal treatments. Treatments range from single layer to multilayer systems, and include different construction techniques such as rejuvenating scrub seal and fiber membrane. Also, a section was crack sealed before the application of a single layer chip seal to assess the benefits. A semi-parametric survival analysis was performed to determine the differences in median time to failure (MTTF) for different chip seal sections versus a controlled section—representing a “do-nothing” scenario. The results showed that the MTTF for a single layer chip seal ranges from 6.8 to 9.1 years depending on the pretreatment condition. Crack sealing before chip seal could extend the MTTF by an additional 1–3 years, depending on initial conditions. Double and triple layer chip seals extend the MTTF beyond 10 years. Finally, the scrub seal provided the highest benefits, with survival rates close to 100% after 10 years of performance.

Experimental study of a porous asphalt

Noise pollution is becoming a crucial problem in France as traffic is rapidly increasing. Therefore, quieter pavements are requested by many communities such as Limoges Metropole. The latter ordered the use of a low noise porous asphalt. This product is used as a wearing course. It is characterized by its phonic properties and improved skid resistance. However, due to its high content of voids (≥ 20%), its mechanical properties might not be as optimal as a conventional asphalt (BBSG: Semi-coarse asphalt concrete). Therefore, this work seeks to determine the durability of the requested porous asphalt experimentally. Tension/compression tests were carried out using samples cored from slabs. The experiments were performed for several temperatures (-10, 0, 10, 15, 20 °C) and frequencies (0.1, 0.3, 1, 3, 10 Hz). The results obtained show that the studied porous asphalt is a decent product compared to other asphalts.

Investigation of Moisture Damage in Open Graded Asphalt Friction Course Mixtures with Basic Oxygen Furnace Steel Slag as Coarse Aggregate under Acidic and Neutral pH Environments

Open graded asphalt friction courses (OGAFCs) are specialty asphalt mixtures used to improve skid resistance and surface drainage. OGAFCs have additional benefits of reduced splash and spray, and lower tire–pavement interaction noise. Prolonged exposure to rainwater and load transfer through stone-on-stone contact in OGAFCs demands aggregates that are strong and hydrophobic. Rainwater acidity is expected to affect the aggregate–asphalt bond and thus moisture damage performance of OGAFC. This paper investigates the effect of rainwater acidity on moisture sensitivity of OGAFC mixtures with different aggregate types (natural aggregate, basic oxygen furnace (BOF) steel slag, and combinations of both) and modified binder types. For the first time, the present research reports the moisture damage potential of BOF OGAFC mixtures under different moisture conditioning environments created by varying the pH of contact water. With different combinations of BOF slag and natural aggregates (100:0, 25:75, 50:50, 75:25, and 0:100), and binders (polymer and crumb rubber modified), OGAFC mixtures were characterized for moisture damage through tensile strength ratio, wet Cantabro abrasion loss, and modified boiling water tests. Functional aspects of OGAFC mixtures subjected to moisture conditioning under different pH environments were also evaluated through permeability testing. Results showed that an acidic environment exacerbated the moisture damage, however, OGAFC mixtures containing BOF slag showed better performance than the control mixture (with natural aggregates only). Inclusion of BOF slag in OGAFC mixtures enhanced resistance to moisture damage under both pH environments. OGAFC mixes with 100% BOF slag content performed the best considering all moisture damage tests under both conditioning environments.

Effect of Mixture Design Parameters of Stone Mastic Asphalt Pavement on Its Skid Resistance

Although it is well known that the stone mastic asphalt (SMA) pavement has good skid resistance, the skid resistance is not satisfactory and its durability is poor when the mixture design is unreasonable. In order to obtain excellent skid resistance for SMA pavement, this paper seeks to analyze the influence of mixture design parameters on the skid resistance of SMA pavement. The mixtures were designed with an orthogonal experiment. There were five factors, namely the percentage of aggregates passing the maximum size (PNMSA), the percentage of aggregates passing the sieve size which is only one smaller than the maximum size (PNMSA-1), the percentage of aggregates passing the control sieve size (PCS), the percentage of aggregates passing the sieve size which is only one smaller than the control sieve size (PCS-1), and asphalt content (AC), and each factor had four levels. The skid-resistance index (SI) obtained by the 3D measurement was used to evaluate skid resistance. The results show that the three parameters (PNMSA, PCS, and AC) are the key parameters to improve skid resistance. Among them, PNMSA has the greatest impact on the skid resistance, AC is the second, and the impact of PCS on skid resistance is the smallest. Moreover, the design parameters with best skid resistance are proposed.

Performance of Chip Seal Treatments in Two Different Climatic Regions

Over time, new pavements deteriorate because of the effect of traffic loads and the environment. Pavement preservation treatments, such as chip seals, are a cost-effective alternative for extending the service life of the pavement without incurring in costly rehabilitation or reconstruction activities. Chip seals are preservation treatments that can help protect the pavement structure, reduce the rate of pavement deterioration, improve skid resistance, and address minor surface problems. As part of the National Center for Asphalt Technology and Minnesota Road Research Facility Pavement Preservation Study, chip seal test sections were placed on low-traffic-volume roads in Alabama and Minnesota. The two locations were selected to represent different climate conditions. Lee County Road 159 in Auburn, Alabama, is subjected to warm, wet, no-freeze climate, while County State Aid Highway (CSAH 8) is located in a cold, wet, freeze area in Pease, Minnesota. Treatments have been in service for approximately 6 years in the southern sections, and 2 years in the northern sections. During this time, cracking, roughness, rutting, and macrotexture data were collected periodically to evaluate pavement performance. The results determined that cracking is a predominant form of distress for these treatments. While the treatments are not expected to address rutting or roughness, the results indicated little variation in the case of the southern treatments, and an increasing trend in international roughness index in the northern sections, likely related to the appearance of thermal cracking. Macrotexture data may be used to assess the functional life of the treatments.

Automated groove identification and measurement using long short-term memory unit

Transverse grooves have been widely used on airport runways to improve their drainage capacity and skid resistance. Therefore, regular measurement and evaluation of groove dimensions on airport runways are significant for runways to improve skid resistance and eliminate hydroplaning risks. However, there are few effective methods that are able to automatically and accurately measure groove dimension. This study introduces a new method for automated groove identification and measurement using Long Short-term Memory (LSTM). The GrooveNet is designed to identify the potential dip and determine two endpoints of the identified dip. Subsequently, dip dimension is calculated according to FAA AC No. 150/5320-12C. Finally, the modified Naïve Bayes classifier is proposed to distinguish grooves and slab joints. Results indicate that the proposed methodology (including GrooveNet and modified Naïve Bayes classifier) is more robust and accurate in runway groove identification and measurement. With the proposed approach, operators of airfield runway pavements have a robust tool to conduct groove safety evaluation and further provide corrective maintenance actions for the unsafe runway grooves.

Effect of Crushed Glass on Skid Resistance, Moisture Sensitivity and Resilient Modulus of Hot Mix Asphalt

Road quality is one of the most important factors concerning the safety of transportation. Adequate skid resistance of a road surface allows drivers to maintain effective control on their vehicles and maneuver when necessary to avoid accidents. Using waste glass in asphalt mixtures is advantageous from the point of technical, environmental and economic perspectives. This study focuses on the topic of asphalt containing crushed glass, also known as glasphalt, by evaluating the skid resistance and moisture sensitivity of these mixtures. Therefore, a laboratory method was used, in which two types of continuous gradation of hot mix asphalt were chosen based on the Iranian highway asphalt paving code (Code No. 234). The fine aggregates, up to 15% of the total aggregate content, were replaced with glass particles in three different gradations. Skid resistance was evaluated in a British pendulum tester, moisture sensitivity by modified Lottman test, and resilient modulus in a UTM machine. Specimens with a moisture sensitivity problem were improved by using zycotherm as an anti-stripping agent. It was found that the crushed glass particles improved skid resistance by up to 20%. The moisture sensitivity test showed that some glasphalts were susceptible to stripping issue, which can be solved by using 0.1% zycotherm in terms of bitumen weight. Finally, findings revealed that glass particles improved resilient modulus of specimens.

Field Performance of Chip Seals for Pavement Preservation

Over time, new pavements deteriorate due to the effect of traffic loads and the environment. If appropriate treatments are applied during the early stages of deterioration, it is possible to extend the service life of the pavement without incurring in costly rehabilitation or reconstruction activities. Chip seals are preservation treatments that can help protect the pavement structure, reduce the rate of pavement deterioration, improve skid resistance, and address minor surface problems. As part of the National Center for Asphalt Technology Pavement Preservation Study, chip seal test sections were placed in a low traffic volume road (Lee County Road 159) in Auburn, Alabama. The location consists of a two-lane county road that provides dead end access to a quarry and an asphalt plant, resulting in a high percentage of heavy loads. At the time of treatment, the existing pavement was 14 years old and consisted of a 5.5 in. hot-mix asphalt layer over a 6.0 in. granular base. Treatments were applied in the summer of 2012 and have been in service for approximately 4.5 years. During this time, cracking, roughness, rutting, and macrotexture data were collected weekly to evaluate pavement performance. The results determined that the performance of the treated sections is highly dependent on the initial condition of the pavement, particularly the percentage of area cracked. Pavements that are treated while still in good condition tend to remain in that category for a longer time. Macrotexture may also be used to evaluate the functional performance of the chip seals.

Identification methods of key contributing factors in crashes with high numbers of fatalities and injuries in China

ABSTRACTObjectives: In China, serious road traffic crashes (SRTCs) are those in which there are 10–30 fatalities, 50–100 serious injuries, or a total cost of 50–100 million RMB (U.S.$8–16 M), and particularly serious road traffic crashes (PSRTCs) are those that are more severe or costly. Due to the large number of fatalities and injuries as well as the negative public reaction they elicit, SRTCs and PSRTCs have become of great concern to China during recent years. The aim of this study is to identify the main factors contributing to these road traffic crashes and to propose preventive measures to reduce their number.Methods: 49 contributing factors of the SRTCs and PSRTCs that occurred from 2007 to 2013 were collected from the database “In-depth investigation and analysis system for major road traffic crashes” (IIASMRTC) and were analyzed through the integrated use of principal component analysis and hierarchical clustering to determine the primary and secondary groups of contributing factors.Results: Speeding and overloading of passengers were the primary contributing factors, featuring in up to 66.3 and 32.6% of accidents, respectively. Two secondary contributing factors were road related: lack of or nonstandard roadside safety infrastructure and slippery roads due to rain, snow, or ice.Conclusions: The current approach to SRTCs and PSRTCs is focused on the attribution of responsibility and the enforcement of regulations considered relevant to particular SRTCs and PSRTCs. It would be more effective to investigate contributing factors and characteristics of SRTCs and PSRTCs as a whole to provide adequate information for safety interventions in regions where SRTCs and PSRTCs are more common. In addition to mandating a driver training program and publicization of the hazards associated with traffic violations, implementation of speed cameras, speed signs, markings, and vehicle-mounted Global Positioning Systems (GPS) are suggested to reduce speeding of passenger vehicles, while increasing regular checks by traffic police and passenger station staff and improving transportation management to increase income of contractors and drivers are feasible measures to prevent overloading of people. Other promising measures include regular inspection of roadside safety infrastructure and improving skid resistance on dangerous road sections in mountainous areas.

Utilizing High Density Polyethylene (HDPE) Synthetic Aggregate as a Chip Sealing Material in Improving Skid Resistance

There are four main factors causing traffic accident : human factor, vehicle factor, road factor and environment factor. Accident data from Poltabes Yogyakarata in 2007 showed that road factor causes accident is 2.45%. In effort to achieve traffic safety, the infrastructure must be considered in the first list. This research is dealing with “Utilizing High Density Polyethylene (HDPE) Synthetic Aggregate as a Chip Sealing Material in Improving Skid Resistance”. The purpose of this research is to understand the effect of chip sealing using HDPE synthetic aggregate on the skid resistance, so that the surface pavement can provide good service for traffic and road users and the quantity of accident can be reduced. In this research the skid resistance was measured using British Pendulum Tester such that the its skid resistance is also called British Pendulum Number (BPN). BPN is a measured based on 3 variations of aggregate weight being spreaded, that are 240 grams, 271 grams and 304 grams. The result of BPN will be correlated with the wet accident ratio, friction coefficient and stopping distance. The BPN values being obtained are 55.96, 55.6 and 53.4, respectively. The BPN was found to increase with the increase of aggregate weight in chip seal mixture. It was revealed that BPN with chip sealing using HDPE could be increased by approximately 10 % in comparison with that without chip sealing. In addition, chip sealing using HDPE can reduce the accident ratio by 47.32 %, improve the traffic safety by 47.32 %, and shorten the stopping distance. The greater friction coefficient the lower stopping distance, and the lower stopping distance the better traffic safety.