Will Shiers reckons the UK’s M4 motorway rivals Route 66. But can he do the whole length of this motorway in a Renault E-Tech T on a single charge?

I’ve developed a bit of a reputation for embarking on unconventional motorway adventures in Renault trucks. In 2008, I spent a dizzying 24 hours continuously circling the M25 – London’s orbital motorway – in a Renault Magnum. Then, in 2020, I completed a full lap of the M25 in an E-Tech D on a single charge.

So, when I asked Renault to loan me its new E-Tech T electric 4×2 tractor for a drive along the M4 – the motorway connecting southern England to South Wales – they weren’t exactly surprised. What did raise a few eyebrows, though, was whether the truck could cover the entire distance on one charge.

With six 90kWh lithium-ion batteries for an installed battery capacity of 540kWh, the E-Tech T offers a range of about 300km, but the M4 is 5km longer. I shared their concern. To improve my odds, I decided to run the truck with a half-payload, hauling 11 tonnes in a curtainsided trailer (the unit’s GVM is 42 tonnes). Even so, with unpredictable traffic and the possibility of bad weather, it would be a close call.

The E-Tech T acquitted itself well.

Before I hit the road, let me set the scene. While the US has its legendary Route 66, celebrated in song and folklore, I’d argue that the M4 offers its own brand of excitement. It might not pass through iconic towns like Amarillo or Gallup, but its 305km is packed with history and character. This motorway links two capital cities, skirts one of the world’s busiest airports, passes near a royal residence, intersects ancient Roman roads, spans Britain’s longest cable-stayed bridge, and even brushes by the hidden ruins of a long-lost town buried beneath the sands of time.

I settle into the cab early one Thursday morning in late August, select ‘drive’, and soon I’m heading west with the E-Tech T’s 490kW (666hp) reaching the road through its 12-speed transmission. Fortunately, the weather couldn’t be better – the sun is shining and expected to stay that way for most of the day. With the low sun at my back, there’s no need to use the electronic windscreen blind.

The journey kicks off on London’s Chiswick Flyover, the very first section of the M4 to be built. This elevated roadway, which cost £6 million ($12 million) to construct, opened in 1959 with a ceremony featuring Hollywood star Jayne Mansfield. Interestingly, the flyover was initially equipped with an under-road heating system to prevent ice and snow build-up, but the technology was never used and eventually fell into disrepair.

From this point, I soon find myself driving beneath the flight path of Heathrow Airport, Europe’s busiest and the seventh busiest globally in terms of passenger traffic. The truck glides almost noiselessly, but the constant roar of planes overhead paints a different picture. The air is thick with the scent of aviation fuel, a stark reminder that trucks aren’t the sole contributors to CO₂ emissions. While heavy trucks are responsible for about 6% of the EU’s total CO₂ emissions, the aviation sector accounts for 3.8%. It’s interesting to consider that there are about million heavy trucks on European roads compared to just 7000 to 8000 commercial aircraft in the skies.

Despite driving against the flow of rush-hour traffic, the westbound carriageway is still quite busy. As I pass a truck, the driver flashes to let me in, and I give a quick burst of the left-right turn signals to acknowledge the gesture. However, things go awry, and I can’t seem to switch them off. That’s when I’m reminded of the latest T’s innovative indicator system: a light press activates a three-flash sequence, while a firmer push causes them to stay on continuously until manually deactivated or the steering wheel returns to its normal position. On dual carriageways or highways, the indicators will automatically cancel once you’ve fully changed lanes, thanks to the lane departure system. It’s impressive tech, but from here on out, I’ll stick with the hazard lights for situations like this.

As I pass Junction 5, the Langley exit, I’m just 2.5km from a significant piece of commercial vehicle history: the former Ford Langley factory. It was here that the original Transit was born, and later, the Cargo was produced. After closing in 1999, the factory was taken over by Iveco and has since been transformed into an industrial estate.

To my left, I catch a glimpse of Windsor Castle, the oldest and largest inhabited castle in the world and the final resting place of Queen Elizabeth II. With traffic easing, the adaptive cruise control takes over, maintaining a steady 87km/h.

The M4 intersects two ancient Roman roads near Swindon: the Fosse Way and Ermin Street. Interestingly, much of the M4 between London and the English city of Bath follows the A4, a route originally laid down by the Romans. For centuries, goods moved west along this same path by horse-drawn carts, only for the advent of the combustion engine in the early 20th century to change everything. Today, we’re on the cusp of another shift as we move toward alternative fuels.

However, the change isn’t instant. The E-Tech T is the only electric truck I’ve seen so far today, and none of the motorway service areas offer truck-charging stations. Still, I won’t need them. By the time I reach Membury Services for a coffee, I’m already a third of the way through the journey, with 70% of the battery charge still intact. Interestingly, this service area sits on the site of the former RAF Membury airfield, used by the RAF and US Army Air Forces during World War II. There are displays and photographs commemorating the personnel who served here, though most drivers are too focused on restrooms and their next coffee to notice.

As I drive through the rolling hills of Gloucestershire, it’s not just the view outside that stands out. The T’s sleeper cab interior impresses me as well. The new 30.5cm digital instrument cluster sits directly in front of the driver, and the 23cm multifunction touchscreen is seamlessly integrated into the dashboard. I also appreciate the multifunction leather steering wheel, with the cruise control buttons now conveniently placed on the front, making it far easier to use, even for those unfamiliar with the vehicle.

A warning sign informs me of severe delays on the Prince of Wales Bridge, which spans the River Severn, linking England and Wales. Opened in 1996, this cable-stayed bridge accommodates a widened M4 across the vast Severn Estuary. I decide to take a slight detour, briefly switching to the M48 to cross the original Severn Bridge instead. Opened in 1966, this bridge once held the title of the world’s longest suspension bridge span and remains an impressive sight to this day.

The E-Tech T covered the 305km journey with range to spare and Will in comfort.

CROESO I GYMRU
(Welcome to Wales)

The M4 passes near Newport’s Celtic Manor Resort, which has hosted two US presidents: George W Bush and Barack Obama. However, my attention is drawn to the Newport Transporter Bridge, visible from the left. Built in 1906, this unique bridge once ferried vehicles across the River Usk. Now a preserved structure, it’s one of the few remaining transporter bridges in the world, though it no longer serves its original purpose.

Between junctions 24 and 28, a strict 80km/h speed limit is enforced. Despite some steep gradients, the E-Tech T handles them effortlessly, with regenerative braking helping to recharge the batteries.

Linking London and Cardiff, the M4 is one of the few roads in the world to connect two capital cities. With a population of over 375,000, the Welsh capital is significant enough to have four dedicated junctions.

As I near junction 35, close to Bridgend, I drive over a stretch of porous asphalt. I remember seeing a TV programme about this innovative surface in the early 1990s. While I assume it’s still in use, the dry weather today doesn’t give me a chance to verify it.

The M4 section passing Pyle and Porthcawl opened in about 1980, and I clearly remember its construction in the late 1970s. With family nearby, I spent much of one holiday watching the work from a spoil heap by an abandoned colliery. I was captivated by the fleet of tippers hauling slag for the new road. I even took some photos, which I still have.

As the motorway stretches on, it passes the Kenfig National Nature Reserve, which holds an intriguing secret. Once a thriving medieval town established in the 12th century, Kenfig was eventually consumed by shifting dunes. By the 15th century, little remained, with only part of its castle still visible today.

Driving past Neath, I’m reminded that I took my truck- driving test here back in 1994. I recall navigating the area in an old Ford Cargo, perfecting the art of double-de-clutching to pass the test. I can still smell the diesel fumes from those early mornings. If someone had told me I’d be back 30 years later in an electric truck, I would have found it hard to believe.

The journey wraps up at Pont Abraham services, the M4’s final stop. The E-Tech T has completed the 305km trip with 15% battery remaining, which the display suggests gives another 60km range. By 2026, Renault plans to release a long-haul version of this truck with a 600km range, meaning I could have turned around and headed back to London. But for now, it’s time for the train home while the Renault Trucks team detaches the trailer and attempts to plug the truck into a car charger.

From a driver’s perspective, the E-Tech T has been a pleasure to drive, but I’m not expecting to convince everyone that electric trucks are the ultimate solution we’ve all been waiting for. Frankly, I don’t fully believe it myself. However, I do hope I’ve managed to inspire those planning a trip to the UK to consider travelling a uniquely British road through a landscape steeped in history.

So, if you ever plan to motor west, travel my way, take the highway that is best. Get your thrills on the M4!