What Is the Most Accurate Equipment for Setting Out Large Highways Projects?

When it comes to setting out highways projects, accuracy isn’t just a target — it’s non-negotiable. A few millimetres off at one end of a carriageway can quickly turn into costly errors in pavement thickness, drainage falls, or alignment. So, what’s the most accurate equipment for the job? Let’s break down what top engineers across the UK rely on — and why.

Engineers carrying out a survey to detect underground utilities on a live highway construction project.

1️⃣ Total Stations – The Backbone of Highway Setting Out

For most large-scale highways projects, the total station remains the gold standard. Modern robotic total stations such as the Leica TS16 or Trimble S9 provide sub-millimetre angular precision and single-operator efficiency.

They’re ideal for control establishment, centreline setting out, kerb lines, drainage runs, and structure positioning. With onboard software (e.g. Leica Captivate or Trimble Access), engineers can upload digital design models directly and set out in real-time against design coordinates.

👉 Why it’s accurate:

• High-precision EDM (Electronic Distance Measurement) up to 0.6 mm + 1 ppm

• Automated target tracking reduces human error

• Seamless integration with CAD and BIM data

If your project involves detailed features like bridge decks or retaining walls, a total station will always outperform GPS alone.

2️⃣ GNSS Receivers – Fast, Reliable, and Perfect for Open Sites

When you’re working on long stretches of dual carriageway or open ground, GNSS (Global Navigation Satellite System) rovers such as the Leica GS18i or Trimble R12i come into their own.

They allow rapid control point establishment, as-built checks, and tie-ins across large areas. For even greater precision, UK contractors use RTK (Real-Time Kinematic) corrections from national networks like SmartNet or Trimble VRS Now, achieving 8–15 mm horizontal accuracy — more than sufficient for earthworks, kerb runs, and service trenches.

👉 Best used for:

• Setting out over large distances

• Earthworks and machine control calibration

• Pre-construction topographical surveys

(Read more about GNSS accuracy and coordinate systems at the Ordnance Survey website.)

3️⃣ Machine Control Systems – Precision in Every Pass

Machine control has transformed how highways are built. By integrating GNSS or total station data directly with excavators, dozers, and pavers, the design model becomes a live guide for operators.

Systems like Leica MC1 and Trimble Earthworks maintain vertical accuracy within 20 mm, minimising rework and material wastage. Engineers can monitor live design compliance, cutting re-survey time dramatically.

👉 Best for:

• Bulk earthworks

• Final trim and sub-base levels

• Embankments and batters

As stated in HSE guidance, machine control also improves site safety by reducing ground personnel exposure near active plant.

4️⃣ Laser Scanners and Drones – The Verification Edge

While not typically used for daily setting out, laser scanners (e.g. Leica RTC360) and drones equipped with RTK-enabled cameras are increasingly used to verify what’s been built. They provide dense, accurate point clouds for as-built surveys, volume checks, and progress validation — crucial for QA documentation and ITRs.

By combining GNSS-based control with scanning data, AKN Engineering produces high-accuracy deliverables that stand up to main-contractor audit requirements.

So, Which Equipment Is “Most Accurate”?

It depends on context.

• For structure-level precision, robotic total stations win.

• For speed and reach, RTK-enabled GNSS is unbeatable.

• For continuous verification, machine control and laser scanning provide the complete picture.

At AKN Engineering, we combine all three — ensuring every kerb line, drainage run, and finished surface meets design within tolerance. Our engineers know when to switch between instruments and how to verify results before handover.

Final Word: Accuracy Is a Process, Not Just a Tool

The most accurate equipment is only as good as its calibration, control network, and operator. Regular instrument checks, known control validation, and disciplined QA processes — including Inspection Test Records (ITRs) — are what keep accuracy consistent across the lifespan of a project.

If you’d like to know how we approach precision setting out on highways projects, or need a setting-out team equipped with the latest total stations, GNSS, and machine control systems — we’re here to help.

👉 Visit www.aknengineering.co.uk or ☎️ call us on 01279 276030 to discuss your next project.