Top UK 10 tunnels new Alfa Romeo Sound Tunnel Index

The best road tunnels in the UK for motorists to enjoy the sound of their cars have been revealed in the new Alfa Romeo Sound Tunnel Index.

Alfa Romeo has teamed up with acoustic experts Sandy Brown to develop a Sound Tunnel Index of the best road tunnels in the UK for motorists to enjoy the sound of their cars. They began by asking Alfa's Alfisti fan base to nominate the UK tunnels that provide the best acoustics. The top 10 were then shared with Sandy Brown, whose experts visited every tunnel.

Each location was rated based on a sound recording of the Stelvio Quadrifoglio performance SUV driving through it. The sound, captured from inside the vehicle, was then assessed by Sandy Brown, one of the UK’s leading acoustic consultancies. Its experts – who led acoustic improvements to the iconic Royal Albert Hall – measured the engine and exhaust sound, plus tyre, road and wind noise, to help rank the findings. Following the objective analysis, Sandy Brown experts then provided a subjective score for each tunnel, with both scores being combined to create the definitive Sound Tunnel Index.

With a one-way traffic system to each of the tunnel’s twin bores, an excellent road surface and a distinctive U-shaped profile, the Penmaenbach tunnel in North Wales was judged to be the tunnel that provided the best acoustic environment in which to enjoy a car’s engine sounds, scoring the highest when the objective vehicle noise analysis was combined with the subjective review by the Sandy Brown team.

In second place was Saltash in Cornwall, proving that high road speeds are not essential to enjoy a tunnel as it is subject to a 30mph speed limit. In fact, without the high levels of wind and tyre noise that can drown out the engine, the V6 Bi-Turbo was clearly audible with only a gentle throttle. In third was Beaminster in Dorset (pictured), the narrow U-shaped design of the tunnel meaning that drivers could hear the engine sound really clearly despite the traffic.

Richard King, Associate at Sandy Brown, said: 'The shape and size of tunnels, their length, the speed of the road, background sounds such as other cars, airflow and tyre noise all have an impact on the sound you hear while driving through them. This is heightened in a performance SUV like the Stelvio Quadrifoglio, where the combination of the V6 Bi-Turbo engine and exhaust sound add to the excitement, so this index will help petrolheads and car lovers across the UK make the most of their drives.'

The passenger window was down during all measurements to ensure the full effect of the engine and exhaust was captured for analysis, and the results were as follows: 

LOCATION LENGTH OBJECTIVE MEASUREMENT SUBJECTIVE RANKING OVERALL RANKING Penmaenbach, North Wales 658m 2nd 1st 1st Saltash, Cornwall 410m 1st 4th 2nd Beaminster, Dorset 105m 3rd 6th 3rd Hindhead, Surrey 1830m 7th 3rd 4th Holmesdale, Enfield 600m 4th 7th =5th Queensway, Cheshire 2010m 9th 2nd =5th Dartford, Kent 1430m 5th 8th =7th Hatfield, Hertfordshire 1200m 8th 5th =7th Limehouse, London 1100m 6th 9th 9th Tyne, Durham 1700m 10th 10th 10th