As part of the development and implementation programme to support the introduction of SCANNER surveys on all local roads in England, this research investigated the potential for using surface texture measurements, on their own or combined with other measurements, to indicate the condition and maintenance requirements of all types and classes of local road, from principal roads to minor unclassified roads.
This research was carried out by TRL Ltd. The final project report is here:
Surface Texture Measurement on Local Roads
The research concluded that the minimum texture depth thresholds used on trunk roads would also be appropriate on principal (A) roads, but texture depth should be measured in both wheel paths on the local roads. It found that texture depth was much more variable on B, C and unclassified roads and a measure of texture depth with a minimum threshold value was much less appropriate.
The project investigated different ways of measuring texture depth variability along and across the road and found that existing systems for measuring longitudinal and transverse profile could provide information about localised changes in surface texture. A method was demonstrated that uses texture data collected across the lane width and combines information about the average level of texture depth, the overall variability and the difference between the centre of the lane and the wheel paths to assess the condition of the surface texture that can be used at a network level.
This report provides background information on assessing noise from road traffic and describes the various noise sources on a vehicle and how they contribute to overall traffic noise levels. Three sources of noise generation need to be considered: Propulsion noise; tyre road noise; and body rattle. The report gives guidance on the likely benefits of low noise road surfaces in different circumstances.
These results have been implemented in the SCANNER User Guide and Specification for 2007.
For scheme level analysis, the information from all the transverse lasers can be displayed to give a visually detailed map, which may help engineers to assess the type and extent of the local areas of deterioration. However, this would require a substantial increase in the amount of data delivered by the survey contractor and stored by pavement management systems and requires further development before it can be incorporated in routine surveys.