What are the benefits of mirrorless trucks?

What took them so long? Miniaturised cameras have been around for ages, yet it’s only within the past six years that Europe’s CV manufacturers have felt sufficiently confident in them to replace tried and trusted rear-view mirrors on a truck.

In fairness, it was never going to be an easy swap. While mirrors provide a threedimensional image, equivalent camera systems are two-dimensional. Depth of vision, assessment of distance, and the closing speed of vehicles from behind all take getting used to seeing on a screen. Mirrors also offer a similar level of sharpness as our eyes; cameras on the other hand have wide-angle lenses and screens with limited resolution, which can make it hard again for drivers to judge distance.

Then there’s the question of where to put the screens. And a screen that’s smaller than an ordinary mirror can affect the size of objects shown on it too. As for those drivers who like sitting closer to the windscreen, a screen mounted on the righthand A-post can almost seem to be ‘in your face’. One way or another, it’s taken technology and cab engineers time to deliver the end goal. For drivers, the journey has only really started.

Introduced in late 2018 at the launch of the ‘new’ Actros (billed as the first series produced truck with cameras instead of exterior mirrors) Mercedes’ MirrorCam has since been joined by DAF’s Digital Vision System, MAN’s OptiView, Scania’s Mirror View Camera (see box, p34), and Volvo’s Camera Monitor System. While MirrorCam is standard on all Actros tractors and rigids, Arocs and eActros models, most competitor systems remain an option – an exception being Volvo’s CMS, standard on all new Aero cabs. 

As for the others, expect Iveco to unveil a camera system later this year (they’re offered on S-Way now, but only as an accessory), while Renault Trucks simply says: “Currently, Renault Trucks does not use camera systems to replace rear-view mirrors. Our mirrors are designed to be as stable, hard-wearing and aerodynamic as possible, supporting safety, aiding fuel economy, reducing noise and minimising dirt deflected towards the cab,” before promising: “We’ll share details of our forthcoming product developments in due course.”

Considering how well mirrors have worked up until now. there has been little incentive to replace them. It’s the classic ‘If it ain’t broke, don’t fix it.’ Okay, on unlit night-time roads they have their limitations (as does the Mk1 eyeball). And in heavy rain, they get covered in muck and spray. Clouting them against a signpost or on-coming truck doesn’t do them any good either. But otherwise, over the years, they’ve done a pretty decent job. 

So, why replace them? Two reasons: safety and fuel economy. In 2006, EU directive 2003/97/EC mandated Europe’s manufacturers to fit improved mirror systems that ensured a better view behind, around the kerbside, and directly in front of all new trucks. It undoubtedly improved things – but ended up creating its own problems. The new larger mirror clusters on both sides of the cab seriously restricted a driver’s lateral view, especially at tight junctions and roundabouts, creating blind spots around the A-posts into which a small car or bike could be easily lost.

Despite commendable efforts by some manufacturers to reduce the size of their mirror mounts and surrounds, the obvious solution has been to do away with mirrors altogether. By fitting small cameras within slim aerodynamic arms mounted well above the driver’s eye-line, backed up by screens fixed inside the cab to the A-posts that mimic conventional mirrors, those previous blind spots have been virtually eliminated.

As for fuel economy, in strong headwinds the drag imposed by large mirror clusters can hit consumption by anything between 1% and 2%. So replacing them with wind-cheating cameras makes sound economic sense as DAF’s UK marketing manager Phil Moon explains: “The specification of our Digital Vision System can offer a significant (>1%) improvement in fuel economy compared with the already aerodynamic conventional mirrors of the New Generation DAF. This can be worth between £500 and £750 per annum in fuel saving.”

As each new system has appeared, they’ve sported features that further reinforce their capabilities. Volvo’s Camera Monitor System (CMS), standard on Aero cabs, offers the opportunity to see better in the dark thanks to what’s called ‘Enhanced Night Vision’. Sitting alongside the normal rear-view and wide-angle camera in each aerodynamic wing is an infrared (IR) lamp which can be activated by a driver at night or in dim light. The cameras ‘read’ the IR light source as it illuminates the area around the truck, providing an enhanced image on the in-cab screen. To activate Enhanced Night Vision, you press a button beneath the screen on the driver side. The improvement in night vision between a conventional rear-view mirror and CMS with Enhanced Night Vision is self-evident.

 While the basic technology used on CMS was developed in North America by Stoneridge on its MirrorEye product, Volvo Trucks’ safety and autonomous & automated driving (ADAS) director Hayder Wokil says CMS has been created very much to the Swedish truck maker’s specification. “Volvo required many features from Stoneridge to be developed exclusively for Volvo, one of them being the IR/Night mode. We also put tougher requirements when it comes to the safety requirement for the Camera Monitor System.”

Referring to the enhanced night vision feature,Wokil adds: “As the colours [displayed on the monitors] will be different, it must be activated manually and temporarily to comply with the legislation.” Once a driver has selected the IR function at night via the button below the driver’s screen, if they don’t deactivate it manually, it will automatically disengage on engine shutdown.  

Considering Volvo’s IR function, it begs the question of whether the same technology that extends night vision behind a truck could deliver a similar improvement in front of it. In August 2009, CM conducted tests with FLIR Systems’ PathFindIR thermal imaging camera, then marketed in the UK by Brigade Electronics, which generated an enhanced view of the road ahead at night, displaying an image on a dashboard-mounted screen. 

Though it worked well we reckoned the future potential for forward-looking IR systems lay in the ability to project an enhanced image of the road ahead onto a truck windscreen via a head-up display, not a monitor. Fifteen years on, when we asked Wokil whether CMS might be developed in that direction, he replied: “Not for the moment.” Meanwhile, Brigade no longer sells a forwardlooking IR camera system, but most of its standard side and reversing blind spot cameras do have IR LEDs that work up to 5-10m in low light.

Whereas Volvo appears to be the first truck maker to fit an IR system on its rear-view cameras, rival makers use other means to improve the low light/ night-time performance of their camera systems, like automatically adjusting the brightness on the screen or allowing a driver to do it manually. On the latest MirrorCam 2, Mercedes uses what it calls new ‘tone mapping’ to improve colour and contrast, as well as night vision. MAN’s OptiView can also filter out the glare caused by dazzling traffic approaching from behind. 

 Looking at the different camera systems, they all have similar features — like automatic trailer tracking where the screen effectively ‘swivels’ (DAF calls it ‘AutoPan’) to always show the rear of the trailer when an artic is turning. Visible sight lines on a screen provide further assistance, especially when reversing. Yet, despite those likenesses, there’s also some divergence when it comes to the actual displays. On DAF’s DVS, Merc’s MirrorCam, and Volvo’s CMS the screens have the normal rear-view as the main display with the wide-angle view below, separated by a dividing line. Conversely, Scania’s Mirror View Camera does it the other way around. 

MAN’s Optiview (optional on all truck models), however, creates what’s called a ‘continuous’ image in the screens, wherein the individual viewing areas from each camera are digitally combined on the screen into a single picture, albeit divided into different zones – the inner portion of the screen up to the top being the main mirror view, while on the outside of the screen and below are the views supplied by the wide-angle and the kerb cameras. The feed from a separate camera on the nearside front corner camera is displayed in the dashboard media system.

Using the door controls, OptiView’s various screen displays can be changed automatically or manually. Above 60kph the screen adopts a zoomed-in view, so vehicles approaching from the rear become more visible. Alternatively, when City automatic mode is selected up to 50kph the wide-angle view predominates, making it easier to spot cyclists and pedestrians.

Despite kick-starting the camera revolution, Mercedes has kept the Class V and VI (kerbside/ front) cab mirrors even when MirrorCam is fitted. According to Stuttgart, from an aerodynamic perspective the two “aren’t really relevant” and “we wanted to make the transition as easy as possible for the driver”. Volvo also keeps Class V and VI mirrors with CMS — but has adapted its previous turn-assist camera system (a popular option since 2020), incorporating it into the CMS camera arm, rather than previously mounted at the base of the old mirror cluster. When indicating left or right, the driver sees a side view of the cab around the classic step-well blind spot on a secondary display in the middle of the dash. The image stays on the screen for three seconds after the indicator is cancelled.

Conversely, MAN and DAF have incorporated Class V and VI mirror functions into their camera systems. When specified, DAF’s Corner View uses a secondary camera mounted on the front nearside quarter panel to display a 285° view around the front nearside corner on a 10in monitor mounted ‘landscape’ on the A-pillar, above the main nearside screen. According to Eindhoven, it’s the natural place for it to be fitted as the combined single view is a lot easier for the driver to see and interpret, rather than having to look at the two previously separatemirrors. When DVS is specified, Corner View is standard on the DAF XD (reflecting its likely urban usage where spotting vulnerable road users is especially important) and optional on XF, XG and XG+ models for £1,250. 

Having offered replacement cameras for longer than any rival, Mercedes has inevitably collected the greatest experience to date. Following criticisms over the length of its mounting arms, as well as camera performance in wet weather, MirrorCam 2 has 100mm shorter mounting arms, while a drip-edge has been added to the camera housing to keep spray away from the lens. 

Shorter mounting arms enable drivers to reverse in a straight line more easily than earlier versions, as MirrorCam 2’s perspective is now more akin to that of conventional glass mirrors. And as the arm protrudes no further than the Class V mirror, striking an object at the edge of the road is, says Mercedes, now “virtually impossible”. With hardware and software upgrades, the latest MirrorCam is said to provide “an even more realistic illustration of the environment and more image information”

Given their traditional conservatism, it will clearly take time before every UK operator embraces replacement cameras – although as more truck makers fit them as standard, the acceptance ‘gap’ will surely close. Moreover, HGV drivers are famed for their adaptability, and if cameras allow them to see better in all weathers and low light conditions, are less prone to damage, and save fuel too, will they really want to go back to mirrors?

That said, if they’re to enjoy their full benefits, a thorough user tutorial must be included in any new vehicle handover. To that end, DAF produces a handy A5 four-page driver guide to DVS covering all the set-up functions, including camera adjustment and controls, plus a warning to fold back the camera arms when using a drivethough vehicle wash!

Even in the relatively short time they’ve been available, cameras have opened up real opportunities to improve driver vision and safety, particularly in urban areas – a fact legislators in Brussels and London are clearly aware of. However, just as with mirrors, drivers can only see one screen at a time. Ultimately, given the speed of technical advances, the real question regarding replacement camera systems is not what they deliver today, but what they might offer drivers and operators in two, five, or 10 years’ time. Even greater night vision? A ‘smart’ zoom-in function that highlights potential danger to a driver on the nearest screen? A closing speed warning on following vehicles? An automatic ‘prowler’ alert for sleeping drivers? If future camera systems deliver more than they do today, then seeing really will be believing...

- This article was previoulsy published in Commercial Motor, to subscribe see the latest Commercial Motor subscription offer