Sector

Highways and bridge drone survey.
Bridge survey, corridor survey and close-range inspection for highway infrastructure.

Survey, inspection and LiDAR across the full highway asset portfolio — from corridor aerial survey for design feasibility through to close-range bridge inspection and as-built LiDAR of highway structures. Delivered with the documentation standards required by National Highways, local highway authorities and principal contractors.

Bridges &
Structures & retaining walls
Corridors &
Drainage & culverts
Highway
Design data
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Highways & Bridges

What survey data does a highway or bridge asset need?

Two datasets, captured off one survey control network. The corridor dataset supports design and maintenance planning: a terrain model, contours, long sections and cross-sections, an orthomosaic and a topographic CAD set across the route extent. The structures dataset supports inspection and asset management: a measured point cloud giving span, headroom and clearance, and close-range imagery compiled into an annotated defect schedule. Both are controlled to OSGB36 and ODN and reported against a stated accuracy band, so corridor and structure data sit together and each survey remains comparable with the next.

Our aerial corridor survey capability supports highway design from feasibility through to detailed design — delivering orthomosaics, LiDAR point cloud, digital terrain models and volumetric data across the full corridor extent. Survey-controlled to OSGB36/ODN with full GCP network, all outputs are traceable to national datum and suitable for engineering use without further adjustment.

Bridge and structure inspection uses a combination of UAV platforms and ground-based camera rigs to achieve the close-range access required for defect identification and condition assessment. Soffit, parapet, abutment and wing wall coverage is achieved without scaffold or lane closure beyond safe working provisions, with all imagery compiled into a structured condition record with annotated defect schedules.

As-built LiDAR of highway structures provides the dimensional data required for clearance analysis, BIM coordination and maintenance planning. Point clouds are delivered in LAS format to client specification and can be processed into CAD cross-sections, surface models or federated into existing BIM environments — giving highway authorities and contractors accurate spatial intelligence across their asset portfolio. Open our Hammersmith Bridge reality model to see a full photogrammetric capture of a Grade II* listed suspension bridge in a browser, or browse all 3D models.

Highway structures

What does a bridge survey include?

A bridge survey records the geometry of the structure and its condition in the same visit. The geometry half is a measured survey of deck, soffit, parapets, bearing shelves, abutments, wing walls and piers, delivered as a point cloud with CAD cross-sections, span dimensions and headroom and clearance figures. The condition half is close-range imagery of every accessible face, compiled into an annotated defect schedule in which each item is tied to a position on the structure. Both are controlled to OSGB36 and ODN off one survey network, so the record is comparable with the next inspection and usable in design without further adjustment.

Geometry and clearance

Span and skew, deck soffit levels, headroom beneath, clearance envelopes for abnormal loads, parapet heights and the dimensional record needed for strengthening design or BIM coordination — cut from a drone and aerial LiDAR survey point cloud and issued as CAD sections in the client specification format.

Condition record

Spalling, cracking, exposed reinforcement, water staining and efflorescence, joint and bearing condition, parapet and safety-barrier damage, scour at piers and abutments — each logged in a severity-ranked schedule with the imagery that evidences it and a position on the structure.

Enclosed substructure

Box girders, bridge voids, culverts and drainage chambers are covered by indoor UAV and handheld SLAM through our confined space and remote inspection service, so no part of the structure is left out of the record because a person could not safely enter it.

Accuracy is specified and reported against the band table in RICS Measured surveys of land, buildings and utilities, 3rd edition (RICS, 2014). The band is agreed at briefing and the residuals achieved against independent check points are stated on issue.

Inspection method

How does a drone bridge inspection work?

A drone bridge inspection flies the structure face by face at close range, recording overlapping imagery of deck edges, parapets, soffit, bearing shelves, abutments and wing walls from positions that would otherwise need scaffold, a mobile elevating work platform or an under-bridge unit. Flights are planned to the structure rather than to a grid: the span, the clearance beneath, what sits below and the traffic management already in place set the flight lines and the stand-off distance. The output is a georeferenced defect register with imagery against every item — evidence for the inspecting engineer, not a substitute for their judgement.

How access is planned

Capture is programmed against traffic management that is happening anyway wherever the inspection cycle allows it. Soffit, pier and abutment coverage over a watercourse or open ground usually needs nothing on the carriageway; deck surfacing, joints and parapets commonly need a lane rather than a full closure, and for a far shorter window than an under-bridge unit requires.

Where the limits are

Imagery does not replace contact testing — cover meter, hammer survey, half-cell potential, bolt torque or coating thickness all need hands on the structure. GNSS is shielded beneath a deck, so positioning there comes from SLAM or from control observed on the ground. High wind closes the window. We state these limits in the survey report rather than at the point a client discovers them.

What you receive

A severity-ranked defect register, paired imagery against every item, a reality model that opens in a browser for the wider project team, and a repeat-survey baseline so the next inspection is directly comparable with this one. Delivered through our aerial drone inspection service.

Background reading: drone infrastructure inspections and asset monitoring.

Highway corridors

What accuracy does a highway corridor survey need?

Enough that long sections and cross-sections can be cut straight from the survey and designed off, which means the accuracy band is agreed at briefing and reported on issue rather than assumed. We specify and report against the band table in RICS Measured surveys of land, buildings and utilities, 3rd edition (RICS, 2014). The corridor is controlled to OSGB36 and ODN with a ground control network spaced along its length, because a long, narrow site is exactly the geometry in which an under-controlled aerial block drifts in height — and height is what a highway design is built on.

Control along the length

Ground control is distributed along the corridor rather than around a block, with check points held back from the adjustment so the residuals quoted in the report are independent of the solution. Where the corridor sits under Traffic Management or inside a rail possession, the control network is observed in the same access window as the flight.

Ground beneath vegetation

Photogrammetry cannot see through a verge hedge or a tree line, so corridors with continuous boundary vegetation are flown with LiDAR for the ground returns and a metric camera for the ortho on the same sortie. Classification separates terrain from vegetation, street furniture and passing vehicles before the terrain model is built.

Comparable over time

Repeat capture off the same control network supports earthworks volumes, settlement and slope monitoring and as-built verification against design formation levels. See road corridor surveys and corridor mapping with Wingtra for the method in full.

Services We Deploy

Which survey methods suit highway and bridge assets?

The aerial, LiDAR and inspection services we deploy across highway corridors and highway structures. Corridor extents are flown as an aerial survey; structures are measured by aerial LiDAR survey and recorded by aerial drone inspection at close range.

Service
Aerial Survey
Survey-controlled corridor aerial survey for design, earthworks and DTM data across highway routes and junction areas.
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Service
Drone & Aerial LiDAR Survey
High-density point cloud for bridge clearance analysis, as-built documentation and BIM integration of highway structures.
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Aerial & Structure Inspection
UAV and camera rig inspection of bridge soffits, deck edges, abutments, retaining walls and parapet structures.
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Reality Capture & 3D Modelling
Photogrammetric 3D models of structures and corridor assets for digital twin creation and asset record management.
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Confined Space & Remote Inspection
Indoor UAV inspection of culverts, bridge voids, drainage chambers and enclosed substructures without manned confined space entry.
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FAQ

Highway and bridge survey questions.

What does a bridge survey include?
A bridge survey records the geometry of the structure and its condition in the same visit. The geometry half is a measured survey of deck, soffit, parapets, bearing shelves, abutments, wing walls and piers, delivered as a point cloud with CAD cross-sections, span dimensions and headroom and clearance figures. The condition half is close-range imagery of every accessible face, compiled into an annotated defect schedule in which each item is tied to a position on the structure. Both halves are georeferenced to OSGB36 and ODN off the same survey control network, so the record is directly comparable with the next inspection and can be used in design without further adjustment.
How does a drone bridge inspection work?
A drone bridge inspection flies the structure face by face at close range, recording overlapping imagery of deck edges, parapets, soffit, bearing shelves, abutments and wing walls from positions that would otherwise need scaffold, a mobile elevating work platform or an under-bridge unit. Flights are planned to the structure rather than to a grid: the span, the clearance beneath, the watercourse or carriageway below and the traffic management in place set the flight lines and the stand-off distance. Where the camera cannot see, the method changes rather than the claim — voids, box girders and bridge chambers are covered by indoor UAV or handheld SLAM instead. The output is a georeferenced defect register with imagery against every item, produced as evidence for the inspecting engineer rather than as a substitute for their judgement.
What accuracy does a highway corridor survey need?
Enough to cut long sections and cross-sections straight from the survey and design off them, which means the accuracy band is agreed at briefing and reported on issue rather than assumed. We specify and report against the band table in RICS Measured surveys of land, buildings and utilities, 3rd edition (RICS, 2014), stating the residuals achieved against independent check points held back from the adjustment. The corridor is controlled to OSGB36 and ODN with a ground control network spaced along its length, because a long, narrow site is the geometry in which an under-controlled aerial block drifts in height, and height is what a highway design is built on.
Can a bridge be inspected without a lane closure?
Often, but not always, and the answer is set by the structure rather than by the drone. Soffit, pier and abutment coverage on a bridge over a watercourse, a railway under possession or open ground is routinely achieved from below and alongside with no effect on the carriageway. Coverage of deck surfacing, parapets, joints and the deck edge usually needs some form of traffic management, although commonly a lane rather than a full closure and for a far shorter window than an under-bridge unit requires. We plan the capture against the traffic management already programmed, so the survey uses a closure that is happening anyway wherever the inspection cycle allows it.
What deliverables does a highway authority receive?
For corridor work: a bare-earth digital terrain model, contours, long sections and cross-sections at the agreed chainage interval, a true-ortho orthomosaic, a classified LAS or LAZ point cloud and a topographic CAD set recording carriageway edges, drainage, street furniture, boundaries and recorded utilities. For structures: a measured point cloud with CAD sections, clearance and headroom figures, a severity-ranked defect schedule with imagery against every item, and a reality model that can be opened in a browser by anyone on the project. Everything is issued in the client specification format with a survey report stating the control, the datum and the accuracy achieved.
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Most scoping responses sent within one business day.

RICS-regulated work, led by Philip M. Angell MRICS.

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