See the Traffic Story: Our New Interactive Heatmap Explained

By Kevin Barry BSc(Hons) MRICS, Quintin QS

Source: Quintin QS TAG Appraisal, March 2026

Introduction

We have published an interactive traffic heatmap for the proposed Strangford Lough Crossing. It is a visual tool built directly on Department for Infrastructure count-point data and the TAG-compliant feasibility appraisal published in March 2026. It is not opinion. It is the evidence — geocoded, colour-coded and interactive. Move the sliders, switch between BEFORE and AFTER, and see for yourself how a 1,111m fixed link redraws the traffic map of South-East Down and the Ards Peninsula.

The Before Picture

Switch the heatmap to BEFORE Bridge and the problem is immediate. The A21 Newtownards corridor carries 42,402 vpd — deep red, saturated, the only meaningful artery in or out of the peninsula. The A22 round-lough route carries 18,197 vpd as the long-way-round alternative. The Ards Peninsula is, in network terms, a dead-end for through traffic.

The Strangford ferry carries just 650 vpd — 83% of drivers avoid it because of cost, wait times and unreliability. And the A25 Downpatrick–Castlewellan–Newry route is barely visible on the map: a chronically underfunded corridor that should be a strategic east–west link but is not treated as one.

What the Slider Shows

Switch to AFTER Bridge and move the slider from 0 vpd upward. The economics turn quickly.

175 vpd — break-even. The bridge covers its own capital cost. Already cheaper than the 60-year ferry liability of £110M (PV).
935 vpd — conservative case. BCR 2.1:1, NPV +£361M.
2,000 vpd — central case. BCR 2.9:1, NPV +£589M.
2,600 vpd — high case. BCR 4.4:1.

The design capacity of the structure is 8,000–12,000 vpd. The bridge is never the constraint — the surrounding network is.

New Corridors Unlocked

The heatmap shows what the bridge makes possible — not just more traffic on existing roads, but new destinations becoming reachable:

Portaferry → bridge → Strangford → Downpatrick → A1 → Newry/Dublin. Currently impossible without a 75km detour.
The Lecale coast warms: Ardglass, Killough and the Ballykinlar GAA Centre of Excellence become viable destinations as the Ards Peninsula opens up as a catchment.
The A25 activates. Downpatrick–Castlewellan–Newry begins to carry the traffic it was built for — and exposes the upgrade need on this historically neglected route.
The A22 round-lough route cools. This is congestion relief, not just new demand.
Cross-border Newry–Dundalk warms at high vpd. Island connectivity, finally.

Economic Activation of Ards and North Down

The bridge does not just move people. It repositions the Ards Peninsula as a location for business. Lower premises costs, fixed-link connectivity, and access to both Belfast and the south of the island make the borough viable for occupiers who today rule it out.

The heatmap shows two-way warming throughout the borough — inbound workers, outbound goods, new residents. DfI economists will scrutinise every figure, and they should. Every number on the map is grounded in the published TAG appraisal (March 2026).

The Bridge Editor

A separate tab lets you position the bridge alignment yourself. Move the four handles — E portal, W portal, Portaferry roundabout, Strangford roundabout — and watch the span update in real time.

Explore the Heatmap

The interactive heatmap is live now: Strangford Lough Crossing — Interactive Traffic Heatmap.

Please share it, embed it on your own sites, and send feedback. The full TAG appraisal is available at quintinqs.com. DfI is the decision-maker. The data is on the table — and it is there for them to scrutinise.

Data Sources

DfI count points: CP444 A20 Kircubbin 14,562 vpd · CP512 A22 18,197 vpd · CP513 A7 Downpatrick 25,336 vpd · A21 Newtownards 42,402 vpd.
Strangford ferry: 650 vpd, £3.52M/yr operating cost, £2.22M/yr net subsidy, 60-year PV liability £110M. Avoidance rate: 83%.
Appraisal: Quintin QS TAG Appraisal, March 2026 — Kevin Barry BSc(Hons) MRICS.See the Traffic Story: Our New Interactive Heatmap Explained
By Kevin Barry BSc(Hons) MRICS, Quintin QS
Source: Quintin QS TAG Appraisal, March 2026