How Road Camber is Calculated

Road camber, also called crossfall, is the transverse slope provided on the pavement surface to facilitate drainage of rainwater away from the carriageway.

When the pavement width and camber percentage are known, the level difference can be calculated using:

Worked Example

Camber from Level Difference

If the measured level difference and pavement width are known, camber can be calculated using:

For example, if the level difference across a 7.0 m pavement width is 175 mm:

Quick Reference – 2.5% Camber

Road Camber – QA/QC Checks

• Verify the approved pavement cross-section and drawings.
• Check the specified camber/crossfall for the pavement type.
• Take levels at the centreline, edges and relevant intermediate locations.
• Compare measured levels with the approved design profile.
• Ensure adequate crossfall is maintained for effective surface drainage.
• Record observations in the relevant inspection or quality-control format.

Engineering Note

Frequently Asked Questions

What is road camber?

Road camber is the transverse slope provided on the pavement surface to facilitate drainage of water from the carriageway.

What is the difference between camber and crossfall?

In highway engineering, the terms are commonly used to describe the transverse slope of the pavement. Crossfall generally expresses the transverse gradient, while camber may also refer to the crowned or sloping road profile.

How is 2.5% camber expressed?

A 2.5% crossfall means a vertical change of 2.5 units for every 100 horizontal units.

Can this calculator be used for site QA/QC?

Yes. It can be used as a quick verification tool when checking pavement levels and crossfall. Final acceptance should always be based on approved drawings and applicable project specifications.