The new traffic-light intersection at Arnarnesvegur and Breiðholtsbraut in Reykjavík has been open only weeks, and it is already generating long queues, angry residents, and serious questions about how a major infrastructure project went so wrong. Traffic engineer Bjarni Gunnarsson, who has publicly criticised the design for five years, calls it a “terrifying and ill-considered” change that contradicts every stated goal of Iceland’s national transport agreement.
Key takeaways
- The junction opened in early July 2026 after three years of construction, but traffic jams appeared almost immediately at peak hours.
- The original plan called for a grade-separated (flyover) interchange; Reykjavík City Council pushed for a signalised junction instead, overriding engineering advice.
- When the design changed, no new environmental impact assessment was carried out — even though the 2003 assessment explicitly listed the signalised option as undesirable.
- Total construction costs on this section of Arnarnesvegur have reached roughly 8 billion ISK, and the mayor of Kópavogi has already called for a redesign.
I drive through this corridor regularly, and even before the new lights opened, it was obvious the approach roads were being built for something bigger than a standard signalised crossing. The four-lane bridge over Breiðholtsbraut — nearly twice the width of the two-lane bridge that would have sufficed for a proper flyover — is a giveaway that the engineering and the politics were pulling in opposite directions throughout.
Why the signalised junction is worse, according to the engineer who warned about it
Bjarni Gunnarsson has been writing about this project in Morgunblaðið for five years, and he says the outcome is exactly what he predicted. Switching from a grade-separated interchange to a signalised junction made the crossing more dangerous, increased delays, lengthened driving distances, and added to vehicle emissions. The irony, he points out, is that the complicated light-controlled layout required a four-lane bridge over Breiðholtsbraut — making the final structure larger and more expensive than the flyover it replaced, not smaller.
He is equally critical of the process. When the Vegagerðin (Icelandic Road and Coastal Administration) agreed to Reykjavík City’s demand and dropped the flyover design, it did not commission a new environmental impact assessment. The agency argued the change was minor — focusing on modest differences in noise levels and claiming the new structure would be smaller. Bjarni flatly rejects that: a four-lane bridge is almost twice the size of a two-lane one, and the assessment said nothing about how the changed design would affect traffic flow. Skipulagsstofnun (the National Planning Agency) accepted this reasoning, so no new assessment was required.
Critically, Vegagerðin had conducted its own road-safety assessment that rated the signalised option significantly worse than the flyover on both safety and traffic-flow grounds. That report was apparently not passed on to Skipulagsstofnun — and, according to Bjarni, was effectively ignored by Vegagerðin itself when it made its final decision. He calls this conduct «ámælisvert» — blameworthy.
The junction now resembles, he says, the notoriously congested intersection at Bústaðavegur and Reykjanesbraut — a crossing that virtually everyone in greater Reykjavík agrees is dangerous and overloaded.
Ásdís Kristjánsdóttir, the mayor of Kópavogi (the municipality immediately south of Reykjavík that the road also serves), has publicly declared a redesign is necessary. She says Kópavogur had already insisted, during the planning phase, that the design include provisions for upgrading to a full flyover if serious congestion emerged — and it has. Bjarni confirms that conversion is technically feasible: the whole project was built with a future flyover in mind. The main change would be rerouting both right-turn lanes, which currently share the bridge, back onto the ground level. But that conversion will take time and money on top of the 8 billion ISK already spent.
Frequently asked questions
Why did Reykjavík City push for a signalised junction instead of a flyover?
City officials objected to including two lanes in the grade-separated design, and they applied political pressure on Vegagerðin to switch to a simpler signalised crossing. Engineers say that decision prioritised politics over evidence, since the road-safety assessment favoured the flyover on every measurable criterion.
Was a new environmental impact assessment done when the design changed?
No. Vegagerðin argued the change was minor, and Skipulagsstofnun accepted that reasoning. Critics point out that the 2003 environmental assessment had already flagged the signalised option as undesirable, and that the agency’s own safety report — which contradicted the decision — was not shared with planners.
Can the junction be converted to a flyover in the future?
Yes, according to Bjarni Gunnarsson. The infrastructure was built with a future flyover conversion in mind, so the engineering groundwork is already there. However, the conversion would require additional investment and time, on top of the roughly 8 billion ISK already spent on this section of Arnarnesvegur.
