Map perimeter weaknesses, run-ups, escape routes, and choke points.
Map where vehicles can build speed and where you can credibly interrupt them. Identify run-up corridors, pinch points, and corner risks to inform HVM bollard array options (321–326) and spacing (232). Balance service-vehicle turning with streetscape and accessibility (237–238). Feed outputs to VDA (221–229) and selection logic (339, 432–435) before fixing foundation types (332). Include one-sentence context that naturally links upward to the parent hubs (this section and the chapter hub). Add SIRA context with a link to SIRA Bollards (UAE) when relevant. Link installation pages only if helpful: What to Expect and Installation Guide.
Important: This is a general guide. For live projects we develop a tailored
Method Statement & Risk Assessment (MS/RA) and align with authority approvals (e.g., SIRA) where in scope.
214.1 Mapping the perimeter
Walk the site edges and plot hard/soft boundaries. Note service gates and informal cut-throughs. Perimeter mapping frames HVM bollard array choices (321) and where a crash rated bollard line is needed most (371).
Start at known access points and follow the full site perimeter. Mark each formal gate and any desire paths that allow vehicles to shortcut curbs. Where edges are ambiguous, record photos and bearings for the Vehicle Dynamics Assessment and frontage protection planning. Capture gradients, camber, and surface type—they influence traction and achievable speed.
| Aspect | What matters | Where to verify |
|---|---|---|
| Performance | Tested system (bollard + footing) | Crash standards overview |
| Operations | Access, duty cycles, fail-state, safety devices & measures | Installation Guide |
214.2 Approach/run-up lines
Identify straight corridors, downhill grades, and long kerb lines (222). These drive HVM bollard density and the crash rated bollard speed band (413).
Map any corridor that lets a vehicle accelerate—these are your run-up distance candidates. Note downhill sections and long, straight kerbs that encourage alignment. Combine these measurements with context from Approach / Run-Up Distance and interpret the resulting speed band with How to read HVM/Crash-Rated ratings. Where run-up is short, low-speed measures may suffice; long run-ups typically point to certified arrays.
214.3 Hard vs soft edges
Walls/planters vs kerbs/landscaping (238). Hard edges can anchor HVM bollard patterns; soft edges may require a certified crash rated bollard to close gaps (232).
Record whether a boundary is structural (wall, planter, grade beam) or deformable (grass verge, painted island). Hard edges can reduce post counts by serving as anchors for array patterns. Soft edges often need a crash-rated closure or re-grading to prevent vehicle lift or bypass.
214.4 Natural vs engineered barriers
Use bends, furniture, and chicanes before adding posts (227, 321). Where residual risk remains, specify HVM bollard arrays and select a crash rated bollard compatible with foundations (332).
Exploit existing deflection—tight bends, tree pits, street furniture—before adding posts. If residual risk remains, select an HVM array that integrates with a feasible foundation class. Cross-check with Foundation types and log constraints for decision flow at 339 Decision Flow.
214.5 Choke points & pinch points
Exploit narrowings to reduce gap counts; avoid pedestrian squeeze (231, 324). Size HVM bollard gaps to pass mobility devices (232). Confirm crash rated bollard head shapes don’t snag (313).
At pinch points, fewer openings mean fewer posts—provided the clear-gap accommodates wheelchairs, prams, and trolleys per People Flow & Egress Widths. Use staggered arrays from Corners, Islands & Pinch Points and verify head profiles from Heads & Attachments don’t create snagging risks.
214.6 Corners and islands
Corners create oblique vectors—treat with staggered arrays/islands (321, 324). Choose HVM bollard geometry that maintains sightlines (237). Check crash rated bollard orientation rules (413).
Vehicles approach corners on oblique approach vectors. Use corner islands or chicanes to force turning and reduce impact energy. Keep sightlines clear for drivers and pedestrians (Sightlines & Signage). Some certified systems have orientation limits—confirm against rating notes in 413.
214.7 Service/turning needs
Reserve turning and staging (325). Provide removable/automatic HVM bollard openings. Ensure any removable crash rated bollard keeps keepered tolerances (421).
Overlay swept paths for refuse, delivery, and emergency vehicles. Where access is required, consider removable (lift-out) or automatic lanes, ensuring the opening is keepered and certified where needed. Reference Turning & Service Access and rating-critical dependencies in 421.
214.8 Blend with streetscape
Coordinate finishes, furniture, and drainage (238, 366, 245). This sustains HVM bollard acceptance and protects crash rated bollard durability (361–363).
Match finishes and street furniture to context while preserving security lines. Coordinate with Streetscape Integration, specify coatings from Color & Aesthetic Finishes, and protect longevity via Environmental Durability Factors. Confirm drainage strategy around foundations (245).
214.9 From map to array options
Translate the plan into two or three viable patterns (321–326) with spacing tables (232). Pair each with a foundation path so a crash rated bollard remains feasible (331–334, 422).
Summarize your findings into 2–3 array patterns with indicative clear-gap rules. For each option, state the assumed foundation class and likely utility conflicts, then carry the short-list to Design checks for foundations and Design selection guide. This keeps the VDA, spacing, and installation practicality aligned.
Related
External resources
- NPSA: Hostile Vehicle Mitigation (HVM)
- FEMA 426 / DHS Reference Manual
- BSI: Vehicle Security Barriers — impact test specifications
214 Perimeter & Approach Paths — FAQ
How do I spot the most critical approach path?
Look for the longest, straightest run-up distance with downhill grade and clear sight to the target. Confirm with Approach / Run-Up Distance and carry the speed band into rating selection.
When are natural features enough without bollards?
If bends, planters, or grade changes force low speeds and remove straight alignments to the target, you may rely on natural calming (227 Terrain & Calming Effects). Where residual risk remains, specify certified arrays.
What clear-gap should I use at pinch points?
Follow the Spacing rules and People Flow & Egress Widths. Ensure mobility devices pass and that head shapes avoid snagging (Heads & Attachments).
How do service openings affect system certification?
Design openings as keepered with removable or automatic lanes. Check rating-critical dependencies to avoid invalidating certificates.