Rearview mirrors on lorries serve one main purpose – to improve the driver’s vision. Conventional rearview mirrors provide lorry drivers with a limited field of vision, with large blind spots around the vehicle. The DREAMS research project – a collaboration between Stoneridge Electronics AB, Scania and RISE – demonstrates that a digital rearview mirror system mounted on a lorry can reduce blind spots, providing the driver with a field of vision that is hard to achieve using conventional mirrors.
A comprehensive evaluation has been carried out in order to obtain knowledge of the safety and usability aspects of digital rearview mirror systems on lorries. Testing was conducted using Stoneridge’s prototype system installed on a Scania lorry. The prototype included cameras mounted close to the front corners of the cab and in-cab digital displays showing real-time video of the driver’s surroundings (equivalent to conventional Class II and Class IV mirrors).
“We have developed a new approach to assessing safety and usability based on our extensive experience of evaluation methods. This is a three-stage process; controlled experimentation at the AstaZero test facility, followed by field testing on public roads and on operating goods vehicles. Evaluations involving over 70 lorry drivers suggests that a high level of safety and usability can be achieved using this system,” says Azra Habibovic, senior researcher and project manager at RISE.
The majority of drivers found the system appealing and easy to get used to; it offers a wide field of vision, particularly at intersections and on roundabouts, and reduces the need for body and head movements to increase visibility. Another advantage of the system is that it provides better vision when side windows are dirty, obscuring conventional mirrors. Replacing conventional rearview mirrors with considerably smaller cameras also reduces wind resistance.
Safety in focus
For Scania, the most important aspect is safety. The company works continuously to improve driver safety and prevent accidents using systems and functions that provide the driver with improved feedback, vision and control.
“Replacing conventional mirrors with digital systems creates a unique opportunity to improve the driver’s view and night vision,” says Hanna Staf, senior vehicle ergonomist at Scania. “This improves safety while at the same time creating a more comfortable work environment for the driver.”
One major challenge is to make the system robust and reliable throughout its working life. Over the course of the research project, Stoneridge has improved the level of technical maturity of the system and they will be further refining their system prior to launching it on the market.
“We have also studied how the functionality of the prototype can be expanded,” says Nicolas Sundberg, development manager at Stoneridge Electronics. “The system currently displays only real-time video of the surroundings; however, in future it should be able to assist drivers in identifying cyclists in blind spots, indicating when it is safe to change lane or display the distance between the lorry and other objects while reversing.”
The research project was co-financed by Strategic Vehicle Research and Innovation (FFI), a partnership programme run jointly by the Swedish state and Swedish automotive industry.
Advantages of digital rearview mirrors
- Increased field of vision at intersections and roundabouts improves road safety.
- Improved night vision creates a safer work environment for drivers.
- Facilitates new functionality that increases the driver’s awareness of road conditions.