Roadside Guardrail & Safety Barrier Evaluator
Evaluate embankment fill height and slope warrants, determine required Clear Zone recovery distances (L_CZ), select barrier types (W-Beam, Thrie-Beam, New Jersey), and calculate Length of Need (L_N) per ERA standards.
Report Metadata
Design Standard Manual Option
Roadway & Hazard Parameters
Mountain Escarpment Drop-off (Fill H = 6.5m >= 3.0m): Severe fatality risk upon run-off. Guardrail MANDATORY per ERA Chapter 10.
Barrier Dimension & Length of Need (L_N) Schedule
ROADSIDE GUARDRAIL & SAFETY BARRIER EVALUATION REPORT
Strictly Formatted per ERA Geometric Design Manual 2013 (Chapter 10) Specifications
| Project Name: | [Insert Project Title] | Date / Time: | 8/10/2026 |
| Section / Station: | [Insert Section Details] | Design Standard: | ERA Geometric Manual 2013 Ch 10 |
| Highway Engineer: | [Insert Engineer Name] | Barrier Status: | MANDATORY |
1. Roadside Hazard & Warrant Assessment
| Design Speed | Fill Height (H) | Side Slope | Clear Zone (L_CZ) | Warrant Conclusion |
|---|---|---|---|---|
| 80 km/h | 6.5 m | 1 : 2 | 7.5 m | BARRIER MANDATORY |
2. Specified Safety Barrier Dimensions & Hardware Schedule
| Specified Barrier Type | Length of Need (L_N) | Total System Length | Post Spacing | Steel Posts Count |
|---|---|---|---|---|
| W-Beam Steel Guardrail | 91.44 m | 116.44 m | 1.905 m | 63 posts |
I hereby certify that the roadside hazard evaluation, clear zone calculation, barrier type selection, and length of need schedule reported herein comply strictly with Chapter 10 of the Ethiopian Roads Administration (ERA) Geometric Design Manual 2013.
Roadside Safety Guidance (ERA 2013 Manual)
1. Clear Zone Concept
The Clear Zone is an unobstructed, relatively flat roadside recovery area allowing errant vehicles to safely recover or stop. Keep all fixed objects at least LCZ meters from the traveled lane edge.
2. Terminal End Anchors
Unprotected W-beam ends are lethal impaling hazards. ERA mandates 12.5m turned-down flared terminals or crash cushions on all leading approach ends.
3. Galvanizing Specification
Per ERA Specification 5400, all steel W-beams, C-posts, and blockouts must be hot-dip galvanized with minimum 610 g/m² zinc coating to withstand tropical weathering.
Roadside Guardrail & Safety Barrier Evaluator Documentation
Technical specifications, mathematical formulas, and civil guidelines
1. Functional Purpose
The Roadside Guardrail & Safety Barrier Evaluator determines safety barrier warrants on high embankments, sharp curves, bridge approaches, and mountain drop-offs according to the ERA Geometric Design Manual 2013 (Chapter 10 - Roadside Safety).
It calculates required Clear Zone distances (L_CZ = 3.0m - 12.0m), selects appropriate containment systems (W-Beam, Thrie-Beam, Concrete New Jersey), and computes exact Length of Need (L_N) and terminal end flare requirements.
2. Practical Workflow Instructions
- Input Corridor & Hazard Data: Enter Design Speed (V in km/h), AADT traffic volume, Embankment Fill Height (H in meters), and Side Slope Ratio (1:m).
- Review Warrant Status: Inspect whether a safety barrier is BARRIER MANDATORY or NOT REQUIRED based on ERA Figure 10-1 fill height vs. slope severity charts.
- Analyze Length of Need (L_N): Review the required W-Beam rail length, leading/trailing terminal flares (12.5m each), post spacing (1.905m or 3.81m), and steel post count.
- Export Print Report: Click Print Clean Report to export a black-bordered professional roadside safety submittal sheet.
3. Mathematical & ERA Standard Basis
Length of Need (L_N) is calculated using ERA Equation 10.4:
Where L_H is hazard offset, L_2 is barrier offset from lane edge, and L_run is runout length (ERA Table 10.3). Total System Length = L_N + 25.0m flares.