Characterizing Rider Safety in Terms of Asphalt Pavement Surface Texture

Quarterly Reports Other Documents Final Report
December 2012
March 2013
September 2013
Research Brief Final Report

Primary Investigator

Hussain Bahia, Ph.D
Department of Civil and Environmental Engineering
University of Wisconsin-Madison


The most significant research effort within the asphalt pavement industry is focused on reducing production and placement temperatures of asphalt mixtures as a means to promote environmental stewardship while maintaining in-service performance. Within the United States, very little emphasis is placed on the functional capabilities of our asphalt pavements, especially in terms of surface texture and friction. As a result, pavements that may perform well mechanically may be functionally unsafe from the rider’s perspective due to a lack of sufficient surface texture (friction). This is not a new problem; several countries within the European Union have already adopted specifications on surface texture to ensure a minimum level of friction.

The challenge associated with moving towards a friction specification for asphalt pavements in the United States is in the friction measurement and analysis methods. Measuring pavement friction directly involves specialized equipment with a relatively high initial cost. Many devices require that measurements be made on field pavement sections, incurring further delay in opening a new pavement to traffic. Several recent studies have correlated asphalt pavement surface texture with friction using relatively inexpensive, non-intrusive devices. These devices can be used in the laboratory as well as in the field and have shown promise in estimating not only pavement surface texture and friction, but also noise emissions and energy usage in terms of vehicle rolling resistance. With further development, these methods will give pavement designers the necessary tools to characterize asphalt pavement surface texture in terms of pavement friction, leading to safer roadways.


This project aims to characterize a significant number of conventional and non-conventional asphalt pavement mixtures to correlate surface texture with friction.


  1. Literature review and development of the final work plan.
  2. Execution of the work plan.
  3. Reporting.

Project Information

  • Duration: 18 months
  • Budget: $146,000 ($87,782 in matching funds)
  • Modal Orientation: Highway
  • Project ID: CFIRE 07-08
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