Best tunnels in Britain: Top 10 revealed with Penmaenbach top

For petrol heads who love nothing more than the rumble of a car engine and growl from its exhaust, this is a top 10 list that will certainly be of interest.

Alfa Romeo has gone out of its way to tell drivers which UK tunnels provide the best acoustics to enjoy the sound of their motors.

The ‘Sound Tunnel Index’ named the 658-metre long Penmaenbach tunnel in North Wales the best in the country – find out which others made the list.  

The Italian car maker has made the index as scientific as possible by partnering with leading acoustic consultants, Sandy Brown, to capture and measure the quality of noise recorded inside its Stelvio Qaudrifoglio SUV while travelling through each UK tunnel.  

The consultancy – which has worked with the Royal Albert Hall to improve its acoustics – used the brand’s 510hp 2.9-litre V6 Bi-Turbo performance car to drive through each tunnel in its ‘Dynamic’ mode, which enhances the exhaust sound. 

The passenger window was wound down during the recordings to ensure the full effect of the engine and exhaust was captured.  

The noise created inside the car was then measured with a sound metre in the passenger seat and analysis of each recording was later reviewed to determine which tunnels were best.

Richard King, an 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 it.’ 

The top 10 order was formulated using a combination of both the objective analysis from the recordings and subjective scores given by the acoustic experts in the vehicle.

Below is a rundown of the top 10 – and if this is your sort of thing you might also like our previous report on the world’s five craziest road bridges motorists can drive across.

10. Tyne Tunnel, Durham (A19)

Length: 1,700 metres

Speed limit: 30mph

The Tyne Tunnel is a pair of two-lane tunnels that run under the River Tyne in North East England and is the first toll tunnel in this list, costing £1.90 for car drivers to use.

A one-way system was the biggest highlight, says the acoustic experts, but it was ranked down for the high levels of vehicle traffic.

Its rectangular profile didn’t make the best of the Alfa Romeo Stelvio’s engine and exhaust sounds. 

9.  Limehouse Link Tunnel, Poplar (A1203)

Length: 1,100 metres

Speed limit: 30mph

This is a 1.1-mile tunnel under Limehouse in East London on the A1203 road and links to Canary Wharf in London Docklands. 

Built between 1989 and 1993 at a cost of £293,000,000, it has been calculated as the most expensive road scheme in Britain per mile – around £50,500 per foot at 2011 prices.

With a long ascent that requires the engine to work slightly harder, and a one-way traffic system, Limehouse tunnel ranked lower down the list due in part to the volume of traffic driving through it, which is typically high at all times – even late at night. 

With a side tunnel merging, this can cause more congestion with drivers switching lanes.

=7. Hatfield Tunnel, Hertfordshire (A1M)

Length: 1,200 metres

Speed limit: 70mph

The Hatfield tunnel was designed in the 1980s to reduce congestion and increase retail space – which is why The Galleria designer outlet is on top of this cut-and-cover tunnel.

Another tunnel with a good one-way traffic system that helps its score, Hatfield is also helped by its motorway speed limit unlike other lower-speed 30mph tunnels seen here.  

It lost points due to the current road surface producing a really loud noise, cancelling out any engine or exhaust growls. Hatfield tunnel does appear to be undergoing road resurfacing works, so might rank higher once completed, Alfa’s study said.

=7. Dartford Crossing Tunnels, Kent (A282)

Length: 1,430 metres

Speed limit: 50mph

One of the most-used tunnels in this list is Dartford Crossing, which has approximately 160,000 vehicles daily using the tunnels and Queen Elizabeth II bridge to cross the Thames. 

The Western tunnel was first used by cars in 1963 and the Eastern tunnel in 1980. They both became northbound only when the bridge was completed in 1991 to take southbound-only traffic. The toll for cars to cross is £2.50.

Acoustic experts said the upward slope in the Dartford tunnel produced a good sound as the engine needs to be engaged to maintain speed, and a one-way traffic system ensures there’s little disturbance from oncoming cars. 

However, because the tunnel is prone to high wind noise and the tar joints on the road surface are very audible when crossing, it missed out on marks. 

=5. Queensway Tunnel, Merseyside

Length: 2,010 metres

Speed limit: 30mph

Liverpool’s Queensway tunnel, which runs under the River Mersey linking the city to Birkenhead. 

Opened in 1934, it’s one of the oldest tunnels in our list and drivers of cars have to pay £1.80 each time to use it.

Despite being a lengthy tunnel with a good road surface, the profiling to the tunnel walls resulted in a ‘ticking’ effect, which impacted the sound measurements taken by the testers. 

The narrow lanes and bumpy road markers also created more noise, distracting from the grumble of the car. 

=5. Holmesdale Tunnel, Enfield (M25)

Length: 600 metres

Speed limit: 70mph

This tunnel is one that makes up the dreaded M25 between the Hertfordshire town of Waltham Cross and the northern fringe of Enfield. 

Alfa Romeo’s studied found that the Holmesdale tunnel is a ‘slight outlier’ with its placing in the top five.

While its rectangular tunnel with four lanes of fast moving traffic wouldn’t always translate to the best engine and exhaust echo, its good road surface and traffic being split into separate traffic sections does improve the sound quality.

4. Hindhead Tunnel, Surrey (A3)

Length: 1,830 metres

Speed limit: 70mph

The Hindhead Tunnel, which only opened in 2011, is part of the four-mile dual-carriageway Hindhead bypass that replaced one of the last remaining stretches of single-carriageway on the A3 linking London to Portsmouth. 

This tunnel is the longest non-estuarial road tunnel in the UK, and takes the road beneath the Devil’s Punch Bowl, a Site of Special Scientific Interest.

Experts inside the Alfa Romeo said the cylindrical bore tunnel has a good road surface and, at 1,830 metres long, is the second-longest tunnel on the list.

As a result, it performed well in subjective tests, with the acoustic engineers said the SUV’s V6 engine note was enjoyable from the cabin. 

3. Beaminster Tunnel/Horn Hill Tunnel, Dorset (A3066)

Length: 105 metres

Speed limit: 60mph (though warning to reduce speed)

While many of the road tunnels in this list are on fast-moving motorways and dual carriageways, this one is set in the stunning countryside of Dorset.

The Beaminster tunnel – also known as Horn Hill tunnel – is the shortest in the list at a mere 105 metres and, having been constructed between 1830 and 1832′ is one of the first road tunnels built in Britain.

Extremely narrow, drivers approaching can be travelling up to national speed limits but are warned to slow due to the skinny construction of the bridge. 

This narrow U-shaped design does acoustically work in its favour on a clear run, though – it means that drivers can hear the engine sound really clearly, say Sandy Brown experts. 

2. Saltash Tunnel, Cornwall (A38)

Length: 410 metres

Speed limit: 30mph

The Saltash Tunnel was opened in 1988 and has an unusual three-lane layout. The central lane operates as a reversible lane to cope with holiday and rush hour traffic. At 410 metres, it is used by more than 38,000 motorists per day.

This tunnel is proof that high road speeds are not essential to enjoy a tunnel in a car. 

Drivers might be restricted to 30mph but 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.

1. Penmaenbach Tunnels, North Wales (A55)

Length: 658 metres

Speed limit: 30mph

Alfa Romeo named the Penmaenbach tunnels in North Wales the best in the UK for petrol heads to enjoy the sound of their motors.

The two tunnels form the A55 trunk road that passes through the Penmaenbach headland, between Conwy and Penmaenmawr, and are different lengths: the shorter tunnel, now normally used by eastbound traffic, was built in the early 1930s while the longer version was constructed some 50 years later.

With a distinctive U-shaped profile, a good road surface and one way traffic configuration in each tunnel, Penmaencbach scored the highest when the vehicle noise analysis was combined with the subjective review by the Sandy Brown team. 

This post first appeared on Dailymail.co.uk