225.1 Defining approach vector

An approach vector is the vehicle’s path and heading at impact. Draw centreline arrows on plans/photos (936) from credible origins (214). This governs HVM bollard pattern orientation and which crash rated bollard orientation limits apply (413, 421).

Start by marking the approach vector from each plausible origin to the target array. Use measured run-up distance (222) and note turning radii and friction surfaces. Your vector choice controls array yaw (angle between array line and traffic flow) and which orientation constraints from the product’s certificate apply (see rating-critical dependencies).

Prefer evidence-led vectors: CCTV timings, kerb strikes, tyre marks, and known desire lines. Document assumptions in the VDA report template (229) and cross-reference your mark-up & overlay standards (936).

225.2 Angle vs penetration risk

Penetration generally rises as angles move from head-on toward shallow glancing. Use angle bands in your VDA (221) to set HVM bollard spacing cushions and to select a crash rated bollard with margin at the governing angle (413).

Define impact angle as degrees from the array normal. Head-on (~90° to the kerb line) tends to maximize energy transfer into the system; shallow angles can increase slide, climb, and residual penetration distance. Use conservative angle bands (e.g., 90°±10°, 60°±10°, 30°±10°) when checking spacing rules in 232.

225.3 Head-on vs glancing blows

Head-on loads maximize axial demand; glancing loads shift to skidding and climb. Choose HVM bollard heads/heights to resist climb (312, 313) and confirm the crash rated bollard test photos/notes match your case (431).

In head-on cases, loads run closer to axial and bending in the primary plane, stressing the foundation’s moment capacity (see 331). Glancing blows create side-scrub, bumper lift, and capture height effects; mitigate by setting effective height and head profile per 312 and 313, and by reviewing certificate imagery/notes in 431.

225.4 Site geometry drivers

Kerb radii, recesses, and islands steer vectors (324, 234). Adjust HVM bollard lines to disrupt shallow entries. Check crash rated bollard certificates for stated approach lanes and offsets (415).

Geometry guides intent: wide kerb returns and recessed doorways invite shallow-angle entries, while corner chicanes and tighter radii induce speed loss and steeper angles. Align arrays with frontage protection logic in 234 and use 324 to disrupt direct run-ups. Always verify the “as-tested” approach lane, offsets, and ground level conditions in 415.

225.5 Multi-approach sites

Corners, bays, and islands create several plausible vectors. Model 2–3 worst-credible cases (226). Select HVM bollard arrays that cover all; ensure the chosen crash rated bollard remains valid for each orientation (421).

List all credible vectors, then down-select to the highest-risk few for analysis in 226. Arrays should provide continuous protection across these vectors—consider mixed-type arrays (326) or additional near-door elements if a second vector threatens a doorway (323). Check 421 dependencies so orientation limits don’t invalidate your selection.

225.6 Selecting worst credible

Pick the highest-consequence, most-likely vector with conservative ± bands (228). This anchors HVM bollard density and your submitted crash rated bollard rating line (413, 938).

Use 228 sensitivity & safety factors to bracket uncertainties in speed, mass, and angle. Document the “worst credible” vector in your submission pack (938) and cite the exact rating string used to justify spacing in 232.

225.7 Diagramming vectors

Overlay arrows, angles, and run-ups on the survey base (248, 222). Clear diagrams speed HVM bollard reviews and shorten crash rated bollard certificate queries (444).

Follow 936 overlay standards: show centreline traces, angle labels, and effective run-up. Reference measured data from 248 survey deliverables and speed methods in 224. Clear vector diagrams reduce back-and-forth when evidencing applicability in 444.

225.8 Evidence photos/overlays

Shoot wide→close sequences with angle notes, kerb clues, and sightlines (716, 237). Evidence supports HVM bollard orientation choices and any crash rated bollard equivalence claim (414).

Use the evidence capture standards (716): wide establishing, mid-range alignment, and close-ups of kerb returns, bollard offsets, and conflict points. Add captions noting approximate angles and sightlines & signage (237). If you assert standards equivalence, align your imagery and notes with 414.

225.9 Reporting angles

State angle ranges, measurement method, and assumptions in 229. Angle clarity stabilizes HVM bollard acceptance and prevents over-stating a crash rated bollard’s applicability (431).

In the VDA report (229), add a “Vectors & Angles” subsection: method (GIS trace, site measurement), angle bands, tolerances, and assumptions register links. Cite any certificate orientation notes from 431 and add a brief authority note with SIRA (UAE) if approvals are in scope.

225 Impact Angles & Approach Vectors — FAQ