Seasonal Signals Observed in Non-Contact Long-Term Road Texture Measurements

Vikki Edmondson,John Woodward,Malal Kane,Owen Ardill,James Martin,Michael Lim

doi:10.3390/coatings11060735

Vikki Edmondson, John Woodward + Show 4 more

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https://doi.org/10.3390/coatings11060735

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Abstract

Texture is required on road pavements for safe vehicle braking and manoeuvres. This paper provides a unique analysis of long-term texture obtained using traffic speed condition survey (TRACS) data from 14 sites, located along a north to south transect spanning the longest highway in the UK. A total of 19 years of sensor measured texture depth (SMTD) data have been analyzed using spatial filtering techniques and compared with meteorological and traffic datasets. The results for hot rolled asphalt (HRA) surfaces reveal that changes to SMTD follow a linearly increasing trend with time. The “rate of change” is influenced by the order of magnitude of annual average daily traffic (AADT), when factored for the percentage of heavy goods vehicles. This linear trend is disrupted by environmental parameters, such as rainfall events and seasonal conditioning. In the summer, this signal is evident as a transient peak in the “rate of change” of texture greater than 0.04 mm, and in the winter as a reduction. The transient changes in texture corresponded to above average rainfall occurring in the week prior to SMTD measurement. The signal observed demonstrates an inverse pattern to the classically understood seasonal variation of skid resistance in the UK, where values are low in the summer and high in the winter. The findings demonstrate for the first time that texture measurements experience a seasonal signal, and provide compelling evidence pointing toward surface processes (such as polishing and the wetting and drying of surface contaminants) causing changes to texture that are affecting seasonal variation in skid resistance.

Highlights

Introduction iationsRoad surface texture is fundamental to safe manoeuvres by vehicles on pavement surfaces [1]
Such research will require measuring in a controlled manner: skid resistance, macrotexture depth, environmental conditions, and monitoring at the macroscale the wetting and drying processes of contaminants on the surface of the pavement. These findings demonstrate that texture measurements experience a seasonal signal and point to a requirement for measuring equipment to be modified to clean pavement surface of detritus prior to readings being taken to achieve more accurate and representative measurement of Sensor measured texture depth (SMTD)
An investigation of the long-term evolution of SMTD for hot rolled asphalt (HRA) surfaces was undertaken for 14 sites located on the north to south transect of the A1(M) in the UK and compared with traffic flow and metrological dataset for 19 years

Summary

Introduction

Introduction iationsRoad surface texture is fundamental to safe manoeuvres by vehicles on pavement surfaces [1]. Texture has previously been defined as having four increasing scales: microtexture, macrotexture, unevenness, and megatexture [2]. Unevenness, megatexture, and macrotexture are routinely monitored at traffic speed, using laser profile sensor techniques and cameras mounted on specialist vehicles [7]. The frictional response to microtexture and macrotexture, whilst surveyed at traffic speed using specialist vehicles, adopts techniques that make contact with a pavement in order to measure skid resistance. These contact techniques frequently make use of a fixed slip rate of braking test wheel [8]

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