cen:proj:81346

Road and airfield surface characteristics — Trailer-based measurement of the rolling resistance of road surfaces. cen:proj:81346

Scope

This document specifies a procedure for trailer-based methods for measuring rolling resistance, under realistic conditions on real road surfaces, for pneumatic reference tyres. Measurement of road surface properties using this method enables comparison to be made between the rolling resistance of road surfaces by using reference tyres when they are free rolling straight ahead, in a position perpendicular to the road surface, and in steady state conditions. For that a towed trailer driving at a constant speed is used.
In measuring tyre-road rolling resistance, it is necessary to measure small forces or angles. It is, therefore, essential that equipment and instrumentation of appropriate accuracy are used. Two main methodologies will be covered: the angle-method and the force-method.
For both methods, the following topics will be treated:
• Choice of the measurement tyre(s) and wheels (including mounting and run-in)
• Tyre load
• Tyre inflation pressure
• The temperature influence
• Meteorological conditions
• The influence of measuring on a slope
• The influence of acceleration/deceleration of the towing vehicle
• The reference speed(s)
• Wheel assembly and alignment
• Protection from wind drag
• Requirements to the test site
• Measurement procedure: warm up procedure, measurement length, lateral/longitudinal position, repetitions etc
• Measured parameter(s): rolling resistance force and wheel load or the direct measurement of the rolling resistance coefficient with the angle method
• Parasitic losses
• Compensations for temperature, accelerations,…
• Presentation of the results
• A template for a measurement report
• Certification of test equipment
• Calibration procedure
The procedure is intended to be suitable for the following applications:
• For the assessment of the rolling resistance of generic or proprietary road surface products.
• For the conformity-of-production (COP) assessment of newly laid surfaces, e.g. to assess compliance with rolling resistance thresholds in standard specifications and/or contract specifications, or to assess the homogeneity of the surface with respect to rolling resistance over its length.
• For the monitoring of the rolling resistance of road surfaces over the course of their working lifetime, so as to help inform surface maintenance/replacement policies and increase understanding of the durability of low rolling resistance road surfaces.
The values derived from this procedure are intended to be used for the following purposes:
• To characterise the initial rolling resistance of a road surface type (making it possible to assign a “road energy label”) using a common procedure across Europe. Such a road energy label will serve as a baseline for setting performance requirements in public procurements, COP assessments and monitoring over the working lifetime of the surface. The label permits the comparison of different road surface types in an unbiased manner.
• To verify the rolling resistance performance and homogeneity of a newly laid road surface.
• To determine the rolling resistance and homogeneity of a road surface at a given point during its working lifetime; the collation of sufficient data on the same surface over time will allow predictions of rolling resistance and may help to drive surface design/development.

In addition, the procedure described within this document also enables the establishment of reference values for wider road surface 'families' or categories of surface types.