A9 Dualling Project: Transforming the Route from Perth to Inverness

The A9 is one of Scotland's most critical transport arteries, connecting the cities of Perth and Inverness. To improve safety and efficiency, Transport Scotland is overseeing a massive upgrade to convert significant portions of the route into a dual carriageway (a road with two separate carriageways for traffic traveling in opposite directions). This ambitious project aims to modernize the driving experience and reduce the high rate of accidents associated with the existing single-carriageway sections.

While the project has faced significant delays and criticism, it remains a cornerstone of Scotland's infrastructure strategy, with a total estimated cost of £3.7 billion.

This dual carriageway section of the A9 is between Dalnacardoch and Dalnaspidal, built in the late 1970s and early 1980s — One of the sections of dual carriageway built in the late 1970s and early 1980s; this is the section in the north of Perthshire between Dalnacardoch and Dalnaspidal

Key Facts

Total Estimated Cost: £3.7 billion.
Project Timeline: Started in 2015 with a target completion date of 2035.
Current Progress: As of October 2025, 35% of the route between Perth and Inverness is dualled.
Future Milestones: 48% completion by 2030, 85% by 2033, and 100% by 2035.
Traffic Volume: Annual average daily traffic (AADT) ranges from 8,500 near Pitlochry to 37,000 near Inverness.

Speed Limits and Road Safety

Safety has been a primary driver for the A9 upgrades. To manage risks on single-carriageway sections, the government has implemented various speed controls. In October 2014, average speed cameras were introduced alongside a 50 mph speed limit trial for HGVs (Heavy Goods Vehicles, defined as vehicles over 7.5 tonnes gross vehicle weight).

Average speed cameras, painted in yellow, operational from late 2024 — The average speed cameras which became operational on the A9 in October 2014, alongside the 50 mph HGV trial

While a proposal to lower the national speed limit on single carriageways from 60 to 50 mph for all vehicles was rejected, there are ongoing discussions to align HGV speed limits with those in England and Wales. Currently, the speed limits for the A9 between Perth and Inverness are as follows:

A9 Speed Limits (mph) - Perth to Inverness
Vehicle Type	Single Carriageway (SC)	Dual Carriageway (DC)
Cars/Motorcycles	60	70
Cars towing trailers	50	60
HGVs	50	-
Buses/Coaches	50	-

Construction Progress and Timeline

The dualling process is being executed in sections. Early successes include the Kincraig to Dalraddy and Luncarty to Pass of Birnam stretches, both of which are now complete.

Construction works for the (now completed) dual section of the A9 near Alvie — Construction works for the first newly completed dual section of the A9 near Alvie

Recent activity has focused on the Tomatin to Moy and Tay Crossing to Ballinluig sections, both currently under construction. Looking ahead, the statutory process for the Pass of Birnam to Tay Crossing section began in May 2025, which will introduce a new roundabout and two grade-separated junctions to improve traffic flow.

Construction work for the second section of the scheme between Luncarty and Pass of Birnam, taken in 2021

The project faces a logistical challenge to meet the 2035 deadline. Transport Scotland has indicated that up to 43 miles of concurrent roadworks may be necessary, though individual work zones will be capped at 15 miles to manage disruption.

Single carriageway section north of the Jubilee Bridge, scheduled for works to start in 2025 — The A9 single carriageway (pictured) north of the Jubilee Bridge is scheduled for dualling in 2025

Detailed Section Status

A9 Dualling Section Breakdown
Section	Length	Status	End of Work
Kincraig to Dalraddy	4.7 mi	Complete	Sep 2017
Luncarty to Pass of Birnam	5.9 mi	Complete	Aug 2021
Tomatin to Moy	6 mi	Under construction	2028
Tay Crossing to Ballinluig	5.1 mi	Under construction	2028
Pitlochry to Killiecrankie	4 mi	In preparation	2030
Pass of Birnam to Tay Crossing	5.2 mi	In preparation	2032
Dalraddy to Slochd	15.6 mi	In preparation	2033
Dalwhinnie to Crubenmore	6.9 mi	In preparation	2033
Crubenmore to Kincraig	10.3 mi	In preparation	2035
Glen Garry to Dalwhinnie	5.9 mi	In preparation	2035
Killiecrankie to Glen Garry	13.8 mi	In preparation	2035

Challenges and Criticism

The project has not been without controversy. The original completion target of 2025 was missed, leading to a revised deadline of 2035. This ten-year delay has sparked criticism from campaigners and political figures who argue that the slow pace of work endangers lives on the "deadliest" sections of the road.

In January 2025, the Scottish Government rejected calls to prioritize the most dangerous sections of the single carriageway, stating that such a shift would not necessarily shorten the overall project timeline. Additionally, some critics have questioned the environmental impact of the project in relation to Scotland's net-zero goals.

Frequently Asked Questions

When will the A9 dualling be fully completed?

The current target completion date for the entire project between Perth and Inverness is 2035.

How much of the A9 is currently a dual carriageway?

As of October 2025, approximately 35% of the route between Perth and Inverness has been upgraded to a dual carriageway.

What is the total cost of the upgrade?

The estimated cost for the dualling project is £3.7 billion.

Why was the completion date pushed back from 2025 to 2035?

The project has faced significant delays, leading the Scottish Government to revise the timeline to ensure all sections can be completed, though specific reasons for the initial delays have been a point of political debate.

What are the current speed limits for HGVs on the A9?

HGVs are currently subject to a 50 mph speed limit on single-carriageway sections of the A9.