Road slipperiness
Road slipperiness is a condition of low
Road slipperiness can be measured either in terms of the friction between a freely-spinning wheel and the ground, or the
Public works agencies spend a sizeable portion of their budget measuring and reducing road slipperiness. Even a small increase in slipperiness of a section of road can increase the accident rate of the section of road tenfold.[2] Maintenance activities affecting slipperiness include drainage repair, snow removal and street sweeping. More intensive measures may include grinding or milling a surface that has worn smooth, a surface treatment such as a chipseal, or overlaying a new layer of asphalt.
A specific road safety problem is
Measurement
The two ways to measure road slipperiness are surface friction testing and stopping distance testing. Friction testing can use surface friction testers or portable friction testers, and involves allowing a freely moving object, usually a wheel, to move against the surface. By measuring the resistance experienced by the wheel, the friction between the ground and the wheel can be found.[1]
Stopping distance testing involves performing an
Measurement of skidding resistance is not yet universally harmononised despite a number of attempts such as
Reduction
Road slipperiness can contribute to
Road slipperiness can be prevented or delayed by proper pavement design. The aggregate used in the pavement should be selected with care, as certain aggregates such as dolomite may polish, or wear smooth under the action of tires. With asphalt pavements and surface treatments, using too much asphalt or asphalt emulsion can cause bleeding or flushing, a condition where excess asphalt rises to the top and fills in the road texture. Both problems increase slipperiness, especially when the pavement is wet.
Once lost,
Snow and ice removal also decreases road slipperiness;
See also
- Anti-skid
- Assured Clear Distance Ahead
- Bleeding (roads)
- De-ice
- Aquaplaning
- Dolomitic limestone
- Epoxy
- Road surface
- SCRIM machine
- Smart highway
- Slipperiness
References
- ^ a b c Dillard, Jack; Mahone, David (1964). "Measuring Road Surface Slipperiness". ASTM Special Technical Publication.
- ^ a b Wallman, Carl Gustav (2001). "Friction measurement methods and the correlation between road friction and traffic safety" (PDF).[permanent dead link]
- ^ FEHRL Report 2006/01 HERMES project, Harmonization of European Routine and research Measuring Equipment for Skid Resistance
- ^ http://www.cen.eu/cen/Sectors/TechnicalCommitteesWorkshops/CENTechnicalCommittees/Pages/default.aspx?param=6208&title=Road%20materials[permanent dead link]
- ^ tyrosafe.fehrl.org
- ^ "Anti-Skid Surfacing Questions (and Answers)". Hoben International Ltd. Archived from the original on 2009-07-19. Retrieved 2010-04-16.
"Volume 7" of the UK Design Manual for Roads and Bridges (DMRB), specifically HD 37/99: Section 5: Part 2: Chapter 11.
TRL Report 298 : Mechanical retexturing of roads : A study of processes and early-life performance. TRL Report 299 : Mechanical retexturing of roads : An experiment to assess durability