HFST is used to significantly improve the friction of road surfaces, making it particularly effective in areas where vehicle control is crucial. Here’s when HFST should be considered:
Accident-Prone Areas
Research by the Federal Highway Administration (FHWA) indicates that HFST is estimated to reduce wet crashes by 83 percent wet-weather crashes and total crashes by 57 percent. Locations with frequent accidents, especially those related to skidding, are prime candidates for HFST. The increased friction can substantially reduce the likelihood of vehicles losing grip, particularly under adverse weather conditions.
The effectiveness of HFST is closely tied to its application in the right locations. Here are the ideal spots for HFST application:
Sharp Curves and Intersections:
According to the FHWA, horizontal curves account for about 25% of highway fatalities, despite comprising only 5% of the total road miles. Applying HFST to sharp curves and intersections, where sudden changes in vehicle speed and direction are common, can significantly reduce crash rates by improving vehicle traction.
Steep Grades:
HFST is particularly effective on steep grades, where loss of vehicle control due to reduced friction is a significant concern. Studies have shown that HFST can reduce crashes on grades by 20-40%, depending on the severity and traffic volume of the location.
Bridges and Overpasses:
Bridges and overpasses often experience different environmental conditions than surrounding roadways, such as increased moisture or freeze-thaw cycles, which can lead to variable friction. HFST helps maintain consistent friction levels, which is crucial for preventing skidding accidents in these areas.
Pedestrian Crossings and School Zones:
The FHWA highlights that HFST can enhance pedestrian safety in high-traffic areas, such as school zones and pedestrian crossings, by improving vehicle stopping distances and control. This treatment is especially effective in reducing accidents in urban settings, where pedestrians are at higher risk.
Highways
HFST can prevent skid resistance by adding grip to the road surface, improving vehicle traction and reducing accidents caused by high speeds in adverse weather.
Junctions
Where vehicles often slow down and accelerate, HFST is crucial to reduce the risk of rear-end and side collisions.
Vehicles navigating horizontal curves may require greater lateral friction compared to those on straight road sections, and vehicles at intersections demand higher longitudinal friction. Consequently, these areas may require pavement with enhanced frictional properties.
Pedestrian crossings
HFST increases skid resistance, which helps vehicles stop in time to allow for pedestrians and other vulnerable road users to cross the street safely.
Traffic calm zones
Residential areas, school zones and play streets can be busy, requiring vehicles to stop unexpectedly. HFST increases skid resistance to ensure that vehicles can travel in a controlled manner, minimising risk of accidents in these areas.
Application process
Proper high-friction surface treatment application is crucial for safety and longevity.
First, the existing road surface is cleaned to remove debris and contaminants, ensuring optimal adhesion.
The binder is then applied to the road surface, followed by the aggregate. Specialist equipment is used to ensure the aggregate is applied in a uniform layer before the binder cures.
Once the HFST has been applied it then takes several hours for the curing process during which time the road would remain closed to traffic.
High friction surface treatment is a proven method for enhancing road safety by reducing skid-related accidents and improving vehicle control. By investing in HFS, road authorities can ensure safer travel for all road users.
