BS EN 1824 relates to road trials used to assess the performance of road markings under real traffic conditions over time. In UK highways procurement, you may see reference to road trials and "roll-over class" terminology such as P5, especially where durability evidence is required for thermoplastic markings in demanding, trafficked environments.
It's one part of a wider evidence picture that can also include material property standards and visibility performance concepts.
Where BS EN 1824 fits in the standards stack
Road trials under traffic
BS EN 1824 (this page)What road trials are used for in practice
Road trials exist because lab tests don't always predict how markings behave after months of traffic, weather, and abrasion. Road trial evidence can help answer:
- How a system performs under real vehicle loading and wear
- How quickly visibility and integrity decline under traffic
- Whether a system remains acceptable in higher-stress conditions
Highways & local authorities →
What "P5 roll-over class" means in a brief
"P5" is a roll-over class tied to durability evidence expectations — a shorthand that the marking system has demonstrated in-service performance under traffic during trials. Don't rely on a single code in isolation. A workable brief should also define:
- Where the marking is being applied (site context and stress zones)
- The visibility intent (night visibility and any wet visibility zones)
- The delivery and evidence expectations (method statement, handover pack)
Why road-trial evidence still depends on site conditions
Even strong durability evidence does not remove the need for good delivery conditions. Premature failures are often driven by:
- Poor or inconsistent surface preparation
- Contamination (oil, rubber build-up, algae)
- Moisture and temperature issues at installation
- Incorrect priming decisions where needed
- High turning/braking forces in specific zones
How to reference BS EN 1824 / P5 in a practical brief
Combine three elements:
1State the durability intent
Especially for high-wear zones
2Define evidence expectations
What documentation bidders must provide
3Define acceptance and snagging
What happens if performance is visibly defective
"For durability-priority zones, provide a thermoplastic road marking system supported by appropriate durability evidence and a method statement covering surface preparation, application method, and bead strategy for visibility where required."
"Provide handover evidence including photos, as-installed notes, and a summary of the installed system and approach."
Quote inputs for durability-led projects
- Drawings/schedules and approximate quantities
- Identification of high-wear zones (approaches, tight turns, braking areas)
- Surface type and condition notes + photos
- Access windows and traffic management assumptions
- Removal/refresh scope where old markings exist
- Visibility intent (night visibility and any wet visibility zones)
Common misunderstandings
'If it's P5, it will last the same everywhere'
Site conditions still drive outcomes. Turning stress, contamination, drainage, and substrate condition can dominate real-world life.
'Durability evidence replaces surface preparation'
It doesn't. Poor preparation can undermine even the best system.
'Road trials only matter for highways'
They're most common in highways procurement, but the concept is useful anywhere performance expectations are high.