FULL REVIEW · 8 SEPTEMBER 2026
Killardry Bridge — How a roadside bank and a new pipe should have been built, drained and left at night
Document type: Full engineering, council-standards, legal, workmanship and wet-tyre review, with footage analysis
Subject site: L-3151 / L3101 approach to Killardry Bridge, County Tipperary
Person: Bronagh English
Collision: after 22:00, 24 April 2025
Working timeline (family site evidence; work-order dates still required):
- Bank / verge cut ≈ 3 weeks before 24 April 2025
- Pipe installed ≈ 1.5 weeks before 24 April 2025
- Family photographs 1 May 2025, GPS-tagged ≈ 60 m from the bridge
Status: Standards and footage review. Not a collision reconstruction. Does not prove clay was under a specific tyre. Does not assign legal liability.
Keywords: Killardry Bridge; Bronagh English; L-3151 Tipperary; roadside clay bank; verge drainage Ireland; TII Series 500; TII Series 600; DN-DNG-03022; DN-GEO-03031; Purple Book road openings; Traffic Signs Manual Chapter 8; Construction Regulations 2013 Regulation 97; Roads Act 1993 s.13 s.76; misfeasance nonfeasance; wet tyre friction; mud contamination; Ford Fiesta 2021; twinwall drainage pipe
1. What this review is — and is not
This review asks five professional questions:
How should a rural verge bank on a local road be formed, sloped, covered and compacted?
How should it be drained, including a newly laid pipe?
What Irish law and council procedure required of anyone who opened that verge?
What does competent workmanship look like on a job that size?
What happens to a passenger-car tyre on a wet, possibly contaminated surface at the speeds this bend allows?
It does not prove that clay was under Bronagh’s tyres. It does not assign legal liability. Irish courts decide that on evidence. The point of setting out the standards is so a reader can see the gap between how this class of work is supposed to be done and what the dated photographs and May walk-through video show on both sides of the lane.
Whose standards apply. Transport Infrastructure Ireland (TII) design manuals and the Specification for Road Works are written for national roads. The L-3151 / L3101 at Killardry is a local road. Tipperary County Council is the road authority. In practice, Irish county engineers use TII Series 500 and 600 as the professional benchmark for drainage and earthworks. The Department of Transport Guidelines for Managing Openings in Public Roads (the Purple Book) prescribe how openings on non-national roads are dug, backfilled and left. Chapter 8 of the Traffic Signs Manual and the Construction Regulations 2013 apply to construction work on any public road.
2. How a bank like this should be built
2.1 What a “verge” is
TII DN-GEO-03036 defines the verge as the part of the cross-section alongside the carriageway, not including cutting or embankment slopes. It is where drainage, ducts and restraint systems live. It is not a spoil heap. It is not an unfinished excavation left open to weather.
On a narrow local lane there is rarely a hard strip. Water leaves the sealed surface across a short edge into whatever the verge has been made into: a grassed fall, a grip, a filter drain, an open ditch, or a pipe and inlet.
2.2 Forming the earthworks (TII Series 600 / CC-SPW-00600)
Clauses that matter for a cut verge face:
Cuttings and other earth faces are to be formed to specified lines and levels, with falls and smooth, closed-up surfaces.
Faces other than rock are to be protected against erosion at all times.
Cutting slopes have a default maximum of 1 vertical : 2 horizontal unless the contract says otherwise, with rounding at toe and crest.
Fill in verges is Class 1, 2, 6 or 9 material, compacted in layers. Topsoil, where used with restraint systems, is capped at about 100 mm.
Permanent drainage is to be installed before bulk excavation reaches 300 mm above formation on a full earthworks job. Cuttings are to be kept well drained at all times. Temporary drains and pumping are required where needed so water does not sit in or on the works.
A 1:2 face is 26.5°. A near-vertical cut clay face is not a Series 600 slope. It is an excavation. If it is left uncovered, it is an unprotected erodible surface.
2.3 Cover and erosion control
Professional practice consistent with Series 600’s “protected against erosion at all times”:
Limit the length of disturbance.
Put permanent or temporary cover on as soon as the face is cut — topsoil and seed, biodegradable matting, or at least a temporary mulch.
Keep runoff off the raw face (up-slope cut-off or interceptor).
Intercept sediment before it reaches the carriageway.
Do not treat “we dug a drain” as the whole control system.
Leaving a freshly cut clay face for three weeks through April rain, then adding a pipe ten days later, is the opposite sequence to “drain first, then expose the minimum face, then cover.”
2.4 What “finished” looks like
A finished rural verge on a local road typically has:
a sealed edge that sheds water
a short, stable fall or a defined channel
vegetation or other cover
no loose stones sitting on the running-surface margin
no unguarded drop a vehicle can fall into
inlets set to level (Purple Book: drainage ironwork flush to 6 mm below adjacent surface, never proud)
3. How it should be drained
3.1 Design purpose (TII DN-DNG-03022)
Speedy removal of surface water to provide safety.
Effective sub-surface drainage to protect the pavement and earthworks.
Control of runoff quality and quantity to the receiving water.
Safety is first. A drain that moves water but leaves mud on the bend has failed the first objective.
3.2 Permitted verge-edge options
For rural roads, kerbs and gullies are not recommended unless there is a footway in the verge. Typical rural choices: combined filter drain; surface-water channel (concrete or grassed); over-the-edge drainage to a ditch; linear units in specific cases.
“Grips” are recognised and criticised: they silt and cut the verge. A newly dug open hole or trench beside a live lane is not a listed finished option. It is a construction state.
Grassed surface-water channels in the specification are triangular or trapezoidal, side slope not steeper than 1 in 5, with 300 mm of granular material and a maximum 100 mm of topsoil, seeded.
3.3 How a pipe should be laid (CC-SPW-00500)
Excavate the trench to line and level.
Lay the pipe on specified bedding, barrel in continuous contact with the bed.
Level tolerance: not more than 20 mm at any point; algebraic difference between two points on one pipe not more than 30 mm.
Surround and haunch as specified, to 300 mm above the barrel.
Backfill immediately after the preceding operations. Compact in layers to Series 600. No power rammer within 300 mm of the pipe.
Trenches in verges: backfill above the surround with Class 1 or 2 general fill unless the contract says otherwise.
Reinstate the surface. Do not leave the trench as an open channel unless the finished design is an open channel with the specified profile and protection.
“Pipe added 1.5 weeks before” only becomes competent work if, by the night of 24 April, the trench had been backfilled, compacted, the inlet set, the outfall working, and surplus spoil off the edge. An open trench with a pipe in it is not a completed drain.
3.4 Surface water on the carriageway (DN-GEO-03031 Chapter 10)
Aquaplaning is partial or full separation of tyre from pavement by a water film. The Gallaway method estimates film depth. For new single carriageways the limit is a maximum film depth of 3.3 mm, and drainage paths should stay near 60 m. Resultant gradient should not fall below about 1%.
A 90-degree rural turn onto a humpback bridge is a place where path length, crossfall change and ponding at the edge all concentrate.
3.5 After a reseal
Overlays raise the running surface. Verge and drainage ironwork have to be brought up to match. A 2025 reseal that is not followed by resetting inlets and re-forming the verge leaves a step: water trapped against a higher sealed edge, or water and fines washing across a lower cut verge.
4. Council and national procedure
4.1 Road authority (Roads Act 1993)
s.13: the county council maintains and constructs local roads. The “road” includes the carriageway, verge, gulley, pipe, kerb and margin.
s.76: power to construct and maintain drains to take water off a public road. Adjoining landowners must not stop road water draining onto their land, and must stop water and soil flowing from their land onto the road. A cut clay face that sheds onto the carriageway is a s.76 soil-on-road issue if the material leaves the works and sits on the public surface.
4.2 The Purple Book
Applies to openings on roads other than national roads.
Determine the excavation corridor with the road authority before work starts.
Longitudinal openings avoid the wheel track where practicable.
No spoil left overnight. Site left clean and tidy at the end of the working day.
Silting of downstream ditches, pipes or catchpits caused by the works is to be cleaned during and on completion.
Backfill and reinstate from trench bottom to surface per Chapter 7 drawings.
Drainage ironwork flush, not more than 6 mm low, never proud.
Standing-water test: intervention if standing water wider than 500 mm or over 1 m² remains for two hours after rain.
Edge depression intervention at 5 mm. Construction tolerance at reinstatement edges 0 / +3 mm.
4.3 Chapter 8 — temporary traffic management
Applies to anyone doing construction or maintenance on a public road.
For a static worksite on a single rural road this normally means:
advance WK 001 Roadworks Ahead
a designed layout matched to speed, visibility and duration (Type A if the site is there more than 12 hours or left in place)
cones and barriers that match the risk, not a single cone
lighting if the hazard remains after dark
a competent person with the right CSCS card supervising signing and guarding
a drive-through check of the installed layout
more frequent inspection in bad weather, including overnight and weekend checks
4.4 Construction Regulations 2013 (S.I. No. 291/2013)
Regulation 97 (works on roads): adequate guarding and lighting appropriate to the circumstances, traffic signs placed and maintained, works supervised by a person with the specified CSCS card. “Others” — the travelling public — are inside the duty.
Regulation 55 (excavations): accessible parts of an excavation where persons could fall are to be fenced or securely covered. HSA guidance: fence excavations in public places; where possible, backfill or cover road excavations at night.
Whether Regulation 55’s fencing duty bites on a shallow verge channel is fact-specific. Regulation 97’s guarding-and-signing duty is broader: if the road was excavated or obstructed for construction, guarding and lighting “appropriate to the circumstances” were required. A bend, darkness, rain and an unfinished edge are circumstances.
4.5 Tipperary County Council
TCC maintains about 4,490 km of local roads and runs a multi-party framework including a drainage lot. A framework contractor still has to meet Series 500, the Purple Book and Chapter 8. Direct labour does too.
Council Internal Review (18 February 2026): only verge-inlet cleaning on the L-3151; no specific drainage works on the bridge; 2025 works northwest of the bridge. That written position has to be read against GPS-tagged photographs of a cut bank ≈ 60 m from the structure and a pipe visible in the turning radius on the May walk-through. Those two accounts cannot both be complete.
5. Legal review
This is not legal advice. It is the framework Irish courts actually use.
5.1 Statutory functions
s.13 Roads Act 1993: function to maintain and construct the local road, including the verge and drains.
s.76: power and related duties on drainage and soil reaching the road.
s.67: road users also have a duty to take reasonable care for their own safety.
Construction Regulations and 2005 Act: duties to workers and “others” when construction is underway.
Chapter 8 / s.95 Road Traffic Act 1961 direction: how temporary signs are provided.
A function is not automatically a private-law duty to every road user.
5.2 Nonfeasance and misfeasance
Nonfeasance — failing to repair or maintain. The old immunity was preserved by Roads Act 1993 s.2(3). Section 60 of the Civil Liability Act 1961, which would have abolished it, was never commenced. Recent Court of Appeal authority has restated that a roads authority is not generally liable merely for leaving a road unrepaired, and has no duty to warn of a danger it did not create.
Misfeasance — doing work, and doing it so as to create a danger. If the authority (or its contractor) cuts a bank, lays a pipe, leaves spoil, or leaves an excavation, that is an act. Negligent performance of that act can found liability.
The family’s three-week / ten-day timeline is legally decisive if it is proved. A bank that had always been there and slowly eroded is closer to nonfeasance. A bank cut three weeks earlier and a pipe dropped in ten days earlier are works. Works are the misfeasance side of the line. Proof is the works order, the gang sheet, the MapRoad licence, photographs dated before the crash, and the vegetation/pipe dating.
5.3 What still has to be proved
Even on a misfeasance theory a plaintiff must still prove: the act, the negligent standard, causation, and foreseeability. Engineering can show the bank was wrong. It cannot, from a 1 May photograph alone, put clay under a specific tyre at 22:00 on 24 April. That needs scene evidence, vehicle examination and, if it exists, sampling.
6. Workmanship review
Competent sequence for a small civil package (cut verge both sides, open channel, new pipe, live rural road, approach to a 90-degree bend and a damaged bridge):
Site-specific risk assessment: bend, darkness, rain, drop to river, existing parapet defect.
TTM design and Chapter 8 layout before the first bucket.
Set out levels: carriageway edge, invert, outfall, cover to pipe.
Install temporary or permanent drainage so the cut does not become a slurry source.
Excavate minimum length; batter or shore; keep spoil off the running surface and off the edge overnight.
Lay pipe to Series 500 tolerances; surround; backfill the same shift if cover allows.
Form the verge to a stable slope; topsoil and seed or mat the face the same week, not “later.”
Set inlet ironwork to Purple Book levels.
Clean downstream silt.
Inspect after rain and after dark before leaving the site live.
Do not leave the site as an open works face for three weeks on a bend.
That table is a workmanship scorecard. It is not a finding that any named person committed an offence.
7. Car and tyre performance
Bronagh was in a 2021 Ford Fiesta. Typical fitments: 195/60 R15, 195/55 R16 or 205/45 R17. Exact size, brand, tread depth and pressure are a matter for the vehicle examination.
7.1 Grip
Peak friction coefficient μ on clean dry asphalt for a good passenger tyre is often around 0.8–1.0. On a wet road it commonly falls into a band around 0.4–0.7 depending on speed, texture, film depth and tread. ABS works in the peak band; it cannot create grip the interface does not have.
7.2 Water film and speed
Classic wet-tyre tests show μ falling as speed rises even in 1.3 mm of water; at 3.8 mm the same tyre reaches hydroplaning-type values at much lower speed. TII’s 3.3 mm film-depth cap exists for that reason. Partial aquaplaning is the usual rural-road event. A 90-degree bend does not need full aquaplaning. It needs a modest cut in lateral μ at the moment the driver asks the front tyres to generate a large cornering force.
7.3 Mud and clay (TRL PPR073)
For cars with tyres in good condition, friction on clay contamination was no worse than might be expected on many wet roads. With smooth tyres, coefficients “practically zero” appeared even on a high-skid surface. Clay slurry under a legal, decent tyre is serious, but it is in the same family as a wet road, not a sheet of ice. Clay slurry under a worn tyre is a different event.
7.4 What this section does not say
It does not say she lost control because of clay. It says: if material from a three-week-old cut bank reached the turning surface on a night with recorded rain, the grip available to any competent driver in a small hatchback would have been a wet-road grip or worse, on a bend that already needed well below 60 km/h in the wet. Causation is a separate proof.
Denis Wood Associates used stated wet-grip assumptions and concluded a significant reduction from the posted 60 km/h was required to negotiate the bend. If μ is lower than they assumed, the available speed falls further.
8. Footage analysis (assets supplied 8 September 2026)
8.1 Three photographic moments — do not mix them
Moment A — the raw toe. IMG_2519 / IMG_2520. Tight on the verge toe. This is the face the argument turns on.
Moment B — the May walk-through. Video IMG_0521.MOV and stills IMG_0513–IMG_0520. Horse-chestnut candles in flower (a May marker). Memorial already on the parapet. This is the geometry of the approach: 90-degree turn, cut on the right into the bridge, cut on the left of the approach, blue pipe end, and the TTM that was left standing.
Moment C — later in the growing season. IMG_2288–IMG_2296 and pipe interiors IMG_2258–IMG_2322. Hogweed / butterbur-scale leaves, nettles, bindweed, a mossy stone kerb half-buried. Same place after weeks of weather. Useful for “the face was never finished,” not for the night of 24 April.
8.2 Zoomed reading of the clay face (Moment A)
The running surface stops. There is no kerb, no channel block, no rounded fillet. The next material is loose, angular stone and wet clods sitting on the sealed margin.
The face above that is near-vertical, not a 1:2 batter.
The soil is dark, cohesive, stone-rich — typical glacial till / clay-bound gravel. When that matrix wets, the fines go into suspension. The stones stay at the toe.
Vegetation on the crest is still a hedge-root mat. The machine cut through an existing bank.
There is no geotextile, no seeded topsoil cap, no silt fence between the face and the wheel track.
That single frame is the workmanship failure in one place: unprotected erodible face + spoil at the running edge + no drainage structure at the toe.
8.3 Right-hand cut into the bridge (Moment B, video 0–8 s; IMG_0518 / 0519 / 0520)
Continuous excavated slot from the junction grass, around the bend, toward the stone parapet.
In the slot, at the tightest part of the turn, a blue twinwall pipe end sits open, almost flush with the cut, no headwall, no grating, no concrete surround.
Beside it: one orange cone and a grey circular sign standing in the excavation, not in a designed lateral safety zone.
Loose brown spoil on the crest and at the toe. Stones already on the grey seal.
A passenger car turning here has a front tyre closest to that toe — the tyre that first meets any slurry or loose stone that has left the face.
8.4 Left-hand approach (IMG_0513–0517)
Linear cut, raw brown face, stones at the edge.
Three cones dropped along the toe, irregular spacing, no Chapter 8 taper.
Offside hedge untouched. The works were a cut along the drainage line, not a redesigned verge.
The “both sides” point is in the photographs: left of the approach lane, right of the turning lane.
8.5 The pipe
Blue inner liner, black corrugated outer — standard twinwall PP/HDPE highway / land-drain pipe (commonly 225–375 mm; this looks toward the larger end).
Daylight at the far end — a through-run, not a blocked stub.
Invert has a silt film.
Mouth set in weeds at ground level. No precast headwall, no masonry, no trash screen, no concrete surround.
Rim chipped — handling damage consistent with a recent install.
In the video at ~2–6 seconds the same blue mouth is in the right-hand cut as you come around the bend. That locates the pipe in the turning radius, not only “northwest of the bridge” as a separate maintenance length.
8.6 What the 42-second video does to the geometry
0–8 s. Tight left-then-right into the bridge. Sightline through the chestnut is short. Right cut and blue pipe in the peripheral field as you commit to the turn.
8–15 s. On the bend. A repaired / open patch in the wheel path. Dark damp streaks across the seal — water is not leaving the carriageway cleanly.
15–25 s. On the deck. Dirt strip, flowers, low broken parapet, then the Aherlow. No containment that meets a modern parapet standard (already-documented 0.23 m residual wall).
The memorial is not evidence of cause. It is evidence of where the road ends. The engineering sequence in one continuous shot: raw cut and open pipe on the approach → tight bend → unprotected deck.
9. Measures that should have been in place that night
24 April 2025 after 22:00. Dark. Rain already in the gauges that day. Live public road. Open excavation on the outside of a 90-degree turn. Unfinished pipe. Known drop beyond the parapet.
9.1 Chapter 8 (static / Type A if left overnight)
One cone and a disc in a hole is not a Chapter 8 layout. It is a marker that someone knew the edge was open.
9.2 Construction Regulations
Regulation 97 applies if the road was opened or obstructed for construction. Lighting and guarding appropriate to a blind wet bend were not optional extras.
9.3 Purple Book end of working day
No spoil overnight. Site clean and tidy. Drainage ironwork set to level. The toe crops fail the first two on their face. The open blue mouth fails the ironwork rule.
9.4 The job should not still have been a worksite
If the bank was three weeks old and the pipe ten days old by 24 April, the night-time “measure” is not more cones. It is that the job should already have been: face battered and rounded; topsoil and seed or matting; pipe surrounded and backfilled; inlet in a headwall or properly set unit; loose stone off the running surface.
9.5 Tyre envelope if those measures are missing
TRL: a legal tyre on clay behaves like a tyre on a wet road, not like a tyre on ice — unless the tread is gone. The face in IMG_2519 is the source term for that contamination: wet cohesive fines plus stones at the exact line a front tyre uses on the turn. The video’s damp streaks show water already using the carriageway as a channel.
10. Combined scorecard
11. Validation checklist — what would make this tighter
Measured shot of the face: staff or tape on the vertical cut and across the stone-strewn toe.
Works order, MapRoad licence, TTM drawing, gang diary — official dates for the three-week / ten-day sequence.
Fiesta tyre size, brand, DOT date, remaining tread, pressure as found.
Any date-stamped image or delivery docket for the pipe at ≈ 10 days.
Night or dusk reconstruction of the approach for TTM visibility.
Scene sampling, if it exists.
Until those sit on the file, the engineering standards are firm and the site description remains the family’s dated photographic case plus the May walk-through.
12. Video chapter list (90–120 seconds each)
Wide approach — both cuts in one frame (IMG_0520).
Push in to the right-hand toe and pipe.
Cut to IMG_2519 — hold on the stones.
Pipe interior — a drain that was never finished as a drain.
Three cones on the other verge — this is not Chapter 8.
Night list on screen: WK 001, taper, lamp, barrier, cover the face. Each item marked absent.
Walk onto the deck — parapet and river.
Hold. No allegation. The missing measures.
Voiceover register: sourced, no personal allegation, Bronagh named as a person not a case number.
Do not say the footage proves clay was under the Fiesta.
Do say the footage proves the edge was an unfinished, unguarded, unlit excavation on the outside of the turn, with an open pipe in the face, and that Irish standards required that state not to exist at 22:00 in the rain.
13. Sources (principal)
TII DN-GEO-03036 Cross-sections and Headroom
TII DN-GEO-03031 Rural Road Link Design, Chapter 10 (surface drainage / aquaplaning / Gallaway)
TII DN-DNG-03022 Drainage Systems for National Roads
TII CC-SPW-00500 Specification for Road Works — Drainage and Service Ducts
TII CC-SPW-00600 Specification for Road Works — Earthworks
TII Standard Construction Details Series 500 and 600 (verge and earthworks drainage)
Department of Transport, Guidelines for Managing Openings in Public Roads (Purple Book), 2nd ed. / Rev 1, and Circular RW 12 of 2025
Traffic Signs Manual Chapter 8 (August 2019) and Temporary Traffic Management Operations Guidance
Safety, Health and Welfare at Work (Construction) Regulations 2013, Regulations 55 and 97
Health and Safety Authority excavation and working-on-roads guidance
Roads Act 1993, ss. 2(3), 13, 67, 76
Court of Appeal restatement of nonfeasance / misfeasance (including the Clare cattle-grid line)
TRL PPR073, Friction tests on contaminated road surfaces (clay, oil, sand)
UNECE R117 / EU tyre wet-grip labelling
Ford Fiesta (CE1) typical tyre sizes and pressures
Met Éireann / family rain-gauge compilation already on the public record (Toureen 21.5 mm on 24 April 2025)
Prepared 8 September 2026 for the family file and for publication planning. Not legal advice. Not a reconstruction.