Observations on the Physical Aspects of Resistance to Skidding on Dry Roads and Particularly on Wet Roads

1956 ◽  
Vol 29 (4) ◽  
pp. 1425-1433 ◽  
Author(s):  
K. Knauerhase
Keyword(s):  
Great Influence ◽  
Boundary Surface ◽  
Road Surface ◽  
Motor Vehicles ◽  
Vector Diagram ◽  
Surface Adhesion ◽  
The Road ◽  
Wet Friction ◽  
Road Surfaces ◽  
Wetting Power

Abstract To ensure safety from skidding, attention has up to now been devoted to building rough surface roads, to the development of the proper vehicle construction with respect to this feature, and to the factor most directly involved, the tires. Special attention has been directed in connection with this latter phase to a much more open tread patterning and to the effect of decreasing tire inflation, both of which affect the life of the tire adversely. These steps neglected to take advantage of the physical effect of adhesion, which, without lowering the durability, now makes possible an enhanced contribution to the cohesive friction by the profile grooves which are of necessity retained to keep the weight down. The goal is, therefore, to provide the smooth surfaces of the tread pattern that come in contact with the road with the greatest possible physical gripping power, or adhesion. After illustrating the interfacial magnitudes with the help of a vector diagram, we shall survey the laws of boundary surface adhesion. Here the great influence of the liquid involved in wet friction becomes clear and the particularly favorable interfacial tension property of water can be assessed. Since skidding can occur only at the interfaces : rubber-water, or water-road, the requirement is as follows : both the greatest possible wetting power between rubber and water, and also between water and road surface, that is, hydrophilic properties in the rubber and hydrophilic road surfaces, in order to reduce the danger of skidding. Good insurance against skidding requires hydrophilic rubber and a hydrophilic road surface, for a tire that has been developed to be nonskidding holds on a hydrophilic road surface and skids on a hydrophobic road surface. A hydrophobic tire, on the other hand, skids on any wet road. Although considerable advances have been made with respect to safety from skidding since rubber tires were first developed for motor vehicles, with increase of speeds this problem demands our attention to a greater and greater degree. Safety from skidding can result only from the combined efforts of road and car builders, tire makers, and the chemists and physicists of all three groups.

Discussion

1968 ◽  
Vol 41 (4) ◽  
pp. 807-831
Author(s):  
W. B. Horne
Keyword(s):  
Friction Coefficient ◽  
Water Depth ◽  
Surface Texture ◽  
Concrete Surface ◽  
Road Surface ◽  
Depth Effect ◽  
Large Aggregate ◽  
The Road ◽  
Wet Friction ◽  
Road Surfaces

Abstract Mr. W. B. Horne (NASA, Hampton, Virginia)—Results in the two papers are in agreement with NASA research results. The papers treated the subjects of tread material, tire construction, road surface texture, and tread design very thoroughly. But one essential ingredient to the problem has been left out of the paper discussions, and that is, the effect of water depth. The importance of the water depth effect, and the need to inform both public and government authorities about the importance of removing worn tires from automobiles for the safety of all, is discussed and illustrated very fully by Leland. An example of what happens when the water depth is 0.4 in. is shown in Figure 1. It can be seen that the water penetrates the tire imprint much more rapidly than in shallow water. The effect of road surface texture on braking friction coefficient is illustrated by the data shown in Figure 2. A smooth tread aircraft tire was successfully braked on five different road surfaces ranging in texture from a large aggregate asphalt surface to wet ice. These surfaces are classified as damp in wetness. The surfaces at the time of testing were wet to the touch but did not have any puddles or standing water. Under this condition, damp smooth concrete (smooth as a table top) gave friction values as low as wet ice. This drastic friction loss decreased as the road surface texture increased. It will be noted that the smooth aggregate asphalt data did not fall off in speed as was shown by Maycock in his paper in Figure 15. In Figure 3 the water depth on the smooth concrete and large aggregate asphalt surface was increased from a damp condition to a flooded condition (0.1–0.2 in.). The character of the friction changes of these surfaces due to change in water depth is remarkable. For example, the smooth concrete increased slightly in value. This is an apparent increase, however, because the deeper water produces a fluid drag term which adds to the tire-surface braking force and gives a higher friction coefficient. This is an academic point, however, since the smooth concrete surface is producing viscous hydroplaning even at low speeds. On the other hand, the asphalt surface which alleviated the viscous hydroplaning effect under damp conditions does not prevent dynamic hydroplaning from occurring to the tire when this surface is flooded to a depth of 0.1 to 0.2 in. To summarize, any surface must be evaluated under a range of water depths before its wet friction qualities can be properly evaluated. Smooth tread tires or badly worn patterned tires have demonstrated poor friction capabilities on most wet or flooded surfaces. For this reason, both aircraft and automobile tires should be removed and replaced before wear produces a smooth tread condition.

Tire-Road Interactions — Harmony or Conflict?

1989 ◽  
Vol 17 (1) ◽  
pp. 66-84
Author(s):  
A. R. Williams
Keyword(s):  
Rolling Resistance ◽  
Major Effect ◽  
Road Surface ◽  
Interactive Effects ◽  
Central Theme ◽  
Water Drainage ◽  
The Road ◽  
Truck Tires ◽  
Road Surfaces ◽  
Tire Wear

Abstract This is a summary of work by the author and his colleagues, as well as by others reported in the literature, that demonstrate a need for considering a vehicle, its tires, and the road surface as a system. The central theme is interaction at the footprint, especially that of truck tires. Individual and interactive effects of road and tires are considered under the major topics of road aggregate (macroscopic and microscopic properties), development of a novel road surface, safety, noise, rolling resistance, riding comfort, water drainage by both road and tire, development of tire tread compounds and a proving ground, and influence of tire wear on wet traction. A general conclusion is that road surfaces have both the major effect and the greater potential for improvement.

scholarly journals Laboratory experiment on the nano-TiO2 photocatalytic degradation effect of road surface oil pollution

2020 ◽  
Vol 9 (1) ◽  
pp. 922-933
Author(s):  
Qing’e Wang ◽  
Kai Zheng ◽  
Huanan Yu ◽  
Luwei Zhao ◽  
Xuan Zhu ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Oil Pollution ◽  
Road Surface ◽  
Test Method ◽  
Driving Safety ◽  
The Road ◽  
Road Surfaces ◽  
The Many ◽  
The Impact ◽  
Degradation Effect

AbstractOil leak from vehicles is one of the most common pollution types of the road. The spilled oil could be retained on the surface and spread in the air voids of the road, which results in a decrease in the friction coefficient of the road, affects driving safety, and causes damage to pavement materials over time. Photocatalytic degradation through nano-TiO2 is a safe, long-lasting, and sustainable technology among the many methods for treating oil contamination on road surfaces. In this study, the nano-TiO2 photocatalytic degradation effect of road surface oil pollution was evaluated through the lab experiment. First, a glass dish was used as a substrate to determine the basic working condition of the test; then, a test method considering the impact of different oil erosion degrees was proposed to eliminate the effect of oil erosion on asphalt pavement and leakage on cement pavement, which led to the development of a lab test method for the nano-TiO2 photocatalytic degradation effect of oil pollution on different road surfaces.

CHARACTERIZATION OF ROAD PROFILES BASED ON FRACTAL PROPERTIES AND CONTACT MECHANICS

2017 ◽  
Vol 90 (2) ◽  
pp. 405-427 ◽  
Author(s):  
Mehran Motamedi ◽  
Saied Taheri ◽  
Corina Sandu ◽  
Pierrick Legrand
Keyword(s):  
Contact Theory ◽  
The Road ◽  
Frictional Properties ◽  
Wet Friction ◽  
Fractal Properties ◽  
Fractal Parameters ◽  
Road Surfaces ◽  
Friction Measurements ◽  
Friction Prediction

ABSTRACT A major challenge in tire and road engineering is to understand the intricate mechanisms of friction. Pavement texture is a feature of the road surface that determines most tire–road interactions, and it can be grouped into two classes of macro-texture and micro-texture. Since the effects of micro-texture and macro-texture dominate the friction measurements at low and high slip speeds, they can help provide sufficient resistance to skidding, if maintained at high levels. A non-contact profilometer is used to measure the macro- and micro-texture of several different road surfaces. The friction number for each surface is measured using the Michigan Department of Transportation's (MDOT) single axle friction trailer. Some fractal parameters of the measured profiles are estimated, and it is proved that all measured profiles display strong fractal behavior. The correlation between texture and fractal parameters and friction is investigated. It is shown that while global fractal quantities fail to classify pavement profiles, the pointwise Hölder exponent as a local fractal parameter, and also the mean square roughness, can discriminate profiles that have different frictional properties. For five road surfaces, two-dimensional (2D) characterization is done using one-dimensional (1D) profile measurements. The hysteretic coefficient of friction is estimated using the contact theory developed by B.N.J. Persson. Good correlation is observed between the wet friction measurements and friction prediction results.

A new procedure for determining the road surface reduced luminance coefficient table by on-site measurements

2018 ◽  
Vol 51 (1) ◽  
pp. 65-81 ◽  
Author(s):  
N Strbac-Hadzibegovic ◽  
S Strbac-Savic ◽  
M Kostic
Keyword(s):  
Road Surface ◽  
Surface Reflection ◽  
The Road ◽  
Road Lighting ◽  
Average Luminance ◽  
Road Surfaces ◽  
Q Values

Numerous measurements have shown that the standard R classes do not represent adequately many road surfaces used nowadays. Therefore, the construction of portable reflectometers intended for on-site measurements of road surface reflection properties has been given particular attention during the last decade. This paper presents a new procedure for the improvement of the accuracy of such a portable reflectometer. Optimally extrapolating the values of the 20 luminance coefficients (q), each measured by the portable reflectometer for a set of angles of observation (α = 5°–80°), the 20 q-values referring to α = 1° are calculated. This enables their comparison with the corresponding q elements from each of the 447 reduced q-tables derived from the available r-table database, obtained by using a precise laboratory reflectometer on a wide variety of road samples. Selecting the closest reduced q-table, the corresponding r-table and the actual average luminance coefficient can be determined. In order to validate the proposed procedure, which can also be applied to other similar portable reflectometers, measurements of the luminance and overall and longitudinal luminance uniformities were carried out on eleven road-lighting installations. They showed that the results obtained by this procedure deviate only slightly from those obtained using r-tables determined by the laboratory reflectometer.

Influence of Test Conditions on Wet Skid Resistance of Tire Tread Compounds

1968 ◽  
Vol 41 (2) ◽  
pp. 477-494 ◽  
Author(s):  
K. A. Grosch ◽  
G. Maycock
Keyword(s):  
Contact Region ◽  
Measuring Method ◽  
Significant Loss ◽  
Road Surface ◽  
Skid Resistance ◽  
Vehicle Speed ◽  
Appreciable Change ◽  
Wet Friction ◽  
Road Surfaces ◽  
On The Road

Abstract This paper is primarily concerned with the skid behavior of tread compounds, and the extent to which testing parameters such as the type of road surface, the vehicle speed, or whether peak and sliding coefficients are considered, influence the skid behavior of one tread compound in relation to another. Whilst the actual braking coefficients depend profoundly on all these parameters the rating of two compounds is much less affected by them. Moreover, subject to the qualification given in the paper, the ranking of compounds will in many cases be predicted correctly by the RRL skid tester. The question arises how the rating of tread compounds will be affected by other testing methods. The three most commonly used are cornering, traction, and stopping distance tests. The first two are dominated by the peak value of the friction coefficient because the measurements are taken just before sliding occurs whilst the last reflects the sliding value of the braking coefficient. Since the rating is virtually the same for these two types of measurement it is likely to be independent of the measuring method. Although the ranking of compounds does not depend on the road surface, well drained road surfaces gave more reproducible results and larger ratings so that fewer readings are required on such a surface than on a flooded one. The following observations as to the nature of wet friction emerge from the present study. (a) Changes in coefficient of friction with tread compound and type of road surface texture confirm the findings of Miss Sabey, and Greenwood and Tabor, that the energy loss component of wet friction on coarse surfaces increases with the sharpness of the asperities, and thus with the pressure on the tops of the asperities. A mechanism for such energy losses based on elastic stored energy is suggested. (b) The decrease in the braking coefficient, as observed on well drained or dry road surfaces after the wheels have become locked, is explained by the frictional temperature rise in the area of contact. (c) It is suggested that in the case of the sliding tire, temperature increase in the contact region with increasing vehicle speed contributes to the observed fall in coefficient with increasing speed. This, together with the temperature dependence of the rubber properties, is used to explain small differences between the speed coefficients of various compounds in their rate of fall off with speed. (d) The mean braking coefficients of the compounds increase with their internal viscosity. It appears that the internal losses can be increased and therefore the skid resistance improved by incorporation of a heavy oil without an appreciable change in the glass transition temperature as measured by a torsion pendulum. This is strikingly demonstrated by the highly resilient natural rubber, whose skid resistance is greatly improved by oil extension without any significant loss in resistance to tire wear.

scholarly journals Perceiving Excitation Characteristics from Interactions between Field Road and Vehicle via Vibration Sensing

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yuansheng Cheng ◽  
Xiaoqin Li ◽  
Xiaolan Man ◽  
Feifan Fan ◽  
Zhixiong Li
Keyword(s):  
Vibration Response ◽  
Road Surface ◽  
Vibration Test ◽  
Agricultural Vehicles ◽  
The Road ◽  
Effective Roughness ◽  
Long Wave ◽  
Road Surfaces ◽  
Road Excitation ◽  
Wave Surfaces

When agricultural vehicles operate in the field, the soft road excitation makes it difficult to measure the vehicle vibration. A camera-accelerator system can solve this issue by utilizing computer vision information; however, the relationship between the field road surface and the vehicle vibration response remains an unsolved problem. This study aims to investigate the correlation of the soft road excitation of different long-wave surfaces with the vehicle vibration response. Vibration equation between the vehicle and soft road surface system was established to produce an effective roughness model of the field soft road surface. In order to simulate the vehicle vibration state under different long-wave road surfaces, the soil rectangular pits with 21 kinds of different spans and depths were applied to the road surfaces, and a tractor vibration test system was built for vibration test. The frequency spectrum analysis was performed for the vibration response and the roughness signals of the road surfaces. The results showed that coefficient (R2) of frequency correlation between the roughness excitation and the original unevenness at the excitation point at the rear end of the rectangular soil pit fell within 0.9641∼0.9969. The main frequency band of the vibration response fell within 0∼3 Hz, and the phenomenon of quadruple frequency existed. The correlation of roughness excitation with quadruple frequency fell within 0.992165∼1. The primary excitation points were located at the rear end of the rectangular soil pit. In addition, it also indicated that when the vehicle was driven without autonomous power, the vehicle vibration frequency mainly depended on the excitation frequency of the field road surface and the frequency at the maximum vehicle vibration intensity was 2 or 3 times of that at the maximum field soft road excitation. These findings may provide a reference for optimal design of vibration reduction and control for agricultural vehicles.

On the applicability of a scan-based mobile mapping system for monitoring the planarity and subsidence of road surfaces – Pilot study on the A44n motorway in Germany

2020 ◽  
Vol 14 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Erik Heinz ◽  
Christian Eling ◽  
Lasse Klingbeil ◽  
Heiner Kuhlmann
Keyword(s):  
Standard Deviation ◽  
Point Clouds ◽  
Road Surface ◽  
Control Points ◽  
Mobile Mapping ◽  
The Road ◽  
Mapping System ◽  
Road Surfaces ◽  
Mobile Mapping System ◽  
Physical Height

AbstractKinematic laser scanning is widely used for the fast and accurate acquisition of road corridors. In this context, road monitoring is a crucial application, since deficiencies of the road surface due to non-planarity and subsidence put traffic at risk. In recent years, a Mobile Mapping System (MMS) has been developed at the University of Bonn, consisting of a GNSS/IMU unit and a 2D laser scanner. The goal of this paper is to evaluate the accuracy and precision of this MMS, where the height component is of main interest. Following this, the applicability of the MMS for monitoring the planarity and subsidence of road surfaces is analyzed. The test area for this study is a 6 km long section of the A44n motorway in Germany. For the evaluation of the MMS, leveled control points along the motorway as well as point cloud comparisons of repeated passes were used. In order to transform the ellipsoidal heights of the MMS into the physical height system of the control points, undulations were utilized. In this respect, a local tilt correction for the geoid model was determined based on GNSS baselines and leveling, leading to a physical height accuracy of the MMS of < 10 mm (RMS). The related height precision has a standard deviation of about 5 mm. Hence, a potential subsidence of the road surface in the order of a few cm is detectable. In addition, the point clouds were used to analyze the planarity of the road surface. In the course of this, the cross fall of the road was estimated with a standard deviation of < 0.07 %. Yet, no deficiencies of the road surface in the form of significant rut depths or fictive water depths were detected, indicating the proper condition of the A44n motorway. According to our tests, the MMS is appropriate for road monitoring.

Paper 2: The Road Surface and Safety of Vehicles

1968 ◽  
Vol 183 (1) ◽  
pp. 68-78 ◽  
Author(s):  
B. E. Sabey
Keyword(s):  
Surface Texture ◽  
Road Surface ◽  
Accident Risk ◽  
Field Surveys ◽  
The Road ◽  
Frictional Properties ◽  
Road Surfaces ◽  
Minimum Requirements ◽  
The Many ◽  
Interpretation Of Results

The control of a vehicle depends ultimately on the friction available between its tyres and the road surfaces to give adequate skidding resistance when wet under the many varied conditions of speed and road layout which are encountered in the course of normal driving. Methods of measuring the skidding resistance of road surfaces are described, with particular emphasis on the interpretation of results in relation to accident risk and on the minimum requirements for safety under different road conditions. The features of road surface texture which give these requirements are outlined and results of field surveys show the extent to which the requirements are met at the present time. The influence of tyre tread characteristics on the frictional properties of road surfaces is also discussed.

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