Why Roadway Slip Testing Matters: Ensuring Safer Surfaces for Everyone

Every year, thousands of road accidents are linked to surfaces with poor skid resistance. Whether it’s a busy intersection, a pedestrian crossing, or a bicycle lane, the grip between tires, shoes, and the pavement is a critical safety factor. That’s where roadway slip testing,  often carried out with the Pendulum Test (ASTM E303, EN 13036-4 / UNI EN 16165), becomes essential. For pedestrian areas, the Pendulum Test is also standardized under BS 7976 in the UK.

This article explores why roadway slip testing is performed, who requires it, and how it improves public safety.

1. Road Safety and Accident Prevention

The main reason for slip testing is simple: safety.

• Surfaces with low friction increase braking distances and the risk of skidding, especially in wet conditions.
  

• High-risk areas such as crosswalks, intersections, roundabouts, or slopes require confirmed skid resistance to protect drivers, cyclists, and pedestrians.

2. Compliance With Standards and Regulations

Authorities around the world mandate slip resistance testing for roads, airports, and public walkways to ensure surfaces remain safe under different conditions. The Pendulum Test is one of the most widely recognized methods, producing results expressed as PTV (Pendulum Test Value) or BPN (British Pendulum Number). These results provide a standardized measure of slip resistance, but they are not the same as a direct coefficient of friction (such as DCOF).

Key standards include:

• ASTM E303 – U.S. standard method describing how to perform the pendulum test, but without specifying “safe” thresholds.
  

• EN 13036-4 / UNI EN 16165 – European pendulum test standards for slip resistance on both pedestrian and vehicular surfaces.
  

• BS 7976 – UK standard for pedestrian surfaces (floors and walkways), not for roads.
  

Compliance with these standards helps agencies and contractors demonstrate due diligence, improve public safety, and reduce liability.

3. Quality Control in Road Construction and Maintenance

Civil engineers and contractors perform slip testing:

• After new road surfacing or resurfacing projects.
  

• When applying anti-skid coatings or high-friction treatments.
  

• As part of quality assurance before handover to public authorities.
  

This ensures that investments in infrastructure deliver lasting performance.

4. Risk Management and Liability Protection

For municipalities, airports, and contractors, proof of testing is also proof of responsibility.

• It protects against legal claims if accidents occur.
  

• Provides documented evidence that the surface met recognized safety standards at the time of inspection.
  

5. Monitoring Performance Over Time

Even the best road surface wears down.

• Traffic, weather, and polishing of aggregate reduce friction levels over time.
  

• Regular pendulum testing helps identify when skid resistance drops below safe levels.
  

• Maintenance can then be scheduled proactively, preventing accidents before they happen.
  

Frequently Asked Questions About Roadway Slip Testing

1. How often should roads be tested for slip resistance?

Testing frequency depends on traffic levels and environmental conditions. High-traffic areas such as intersections, crosswalks, and roundabouts should be checked annually, while lower-risk roads may be tested every 2–3 years. Authorities may also require testing after resurfacing or applying new coatings.

2. What is considered a safe slip resistance value for roadways?

The Pendulum Test provides a Pendulum Test Value (PTV), also called the British Pendulum Number (BPN).

• ASTM E303 specifies how to perform the test but does not define a “safe” threshold.
  

• EN 13036-4 / UNI EN 16165 (Europe) consider a PTV above 36 to indicate low slip risk for pedestrian areas.
  

• In the UK (HSE guidelines), a PTV of 36 or higher is classed as low slip potential, while higher thresholds (around 40–45+) are often recommended for external and high-risk areas such as pedestrian crossings and cycle lanes.
  

Thresholds may vary by country and application, but generally PTV ≥36 is the minimum benchmark, with stricter values applied where safety is critical.

3. Which standards are used for roadway slip testing?

The most recognized standards include:

• ASTM E303 (U.S., method only)
  

• EN 13036-4 / UNI EN 16165 (Europe)
  

• BS 7976 (UK, pedestrian areas only)
  

All rely on the Pendulum Test to provide a standardized PTV/BPN result.

4. Who carries out roadway slip testing?

Typically, civil engineering firms, contractors, and accredited testing laboratories perform the tests. Local municipalities, airports, and transport authorities often require certified results.

5. Why not just rely on visual inspections?

A surface may look fine but still be dangerously slippery, especially when wet or polished by traffic. Only standardized testing with equipment like the British Pendulum Tester provides objective, reliable results.

6. Can slip resistance be improved if a road fails testing?

Yes. Treatments include applying anti-skid coatings, high-friction surfacing, grooving, or resurfacing with aggregates designed to provide better grip.

Conclusion

Roadway slip testing is more than a technical procedure — it’s a cornerstone of public safety. From highways to crosswalks, ensuring the right level of slip resistance reduces accidents, saves lives, and builds trust in infrastructure.

The Pendulum Test remains one of the most recognized methods worldwide:

• ASTM E303 and EN 13036-4 / UNI EN 16165 are used for road and outdoor surface testing.
  

• BS 7976 is applied mainly to pedestrian surfaces, such as walkways and floors, particularly in the UK.
  

Together, these standards help engineers, authorities, and safety managers confirm that surfaces are fit for purpose.