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March 2026 snapshot

A417 AIR BALLOON

Infrastructure and Construction

Official NISTA record

Record date: 31 March 2026

Whole-life cost
£542.6m
Published schedule
01/04/2015 – 31/08/2027
NISTA delivery confidence
Not disclosed
Senior responsible owner
Colin Bird

What the project is for

As announced in the Roads Investment Strategy 2, the scope includes improving the A417 with a scheme that includes: - 4 miles of new dual carriageway connecting the existing A417 Brockworth bypass with the existing A417 dual carriageway south of Cowley - a section to the west of the existing Air Balloon roundabout that will follow the existing A417 corridor. However, the section to the south and east of the Air Balloon roundabout will be offline, away from the existing road corridor - a new junction at Shab Hill, providing a link from the A417 to the A436 towards Oxford and into Birdlip - a new junction near Cowley, to replace the existing Cowley Roundabout - the existing A417 between the Air Balloon roundabout and the Cowley Roundabout is being repurposed. We are converting some lengths of this existing road into a route for walkers, cyclists and horse riders, while retaining other sections to maintain local access for residents.

Departmental delivery commentary

Compared to financial year 24/25 Q4, the NISTA/SRO Delivery Confidence Assessment (DCA) rating at 25/26 Q4 remained at green. This is primarily due to the following factors that the project is progressing to schedule and on track for Open for Traffic in Quarter 4 Financial Year 26-27.

Schedule

Compared to financial year 24/25-Q4, the project's end-date at 24/25-Q4 remained at 31/08/2027. This is primarily due to the following factors, that the project remains on schedule.

Cost

Compared to financial year 24/25-Q4, the project's departmentally agreed Whole Life Cost at 25/26-Q4 (measured in £m) increased from 535 to 542.63. This is primarily due to the following factors that our Whole Life forecast costs have been converted into a different price base (or nominal) if it wasn't for this the costs would have remained unchanged.

Benefits

Compared to financial year 24/25-Q4, the project's departmentally agreed Benefits at 25/26-Q4 (measured in £m) decreased from 424 to 233.06. This is primarily due to the following factors that the figure has been converted into a different price base (or nominal) if it wasn't for this the predicted benefits would have remained unchanged.