Being visible in the traffic is a guarantee of safe motorcycle riding, provided that living people are sitting behind the wheel of the cars. However, in reality, when automakers staged a real race to bring self-driving cars to the road, motorcyclists faced another difficulty: now you need to be visible not only for people, but also for robots.
Modern cars, be they self-driving or with a live driver, are equipped with a variety of safety systems that reduce the likelihood of causing a serious accident, but motorcyclists are sometimes invisible to these systems. In particular, this applies to radars: new cars are increasingly equipped with adaptive cruise control and collision avoidance system based on forward-looking radar, and these functions are able to resort to emergency braking fully automatically if they detect too fast approach to an obstacle or passing vehicles, but they they are far from always able to recognize such a small object as a motorcyclist or scooter. Worse, plastic or composite hoods have virtually no radar reflectivity, unlike metal auto body panels, and are therefore even less noticeable to radar-based security systems. In the not too distant future, when cars will be self-driving (or with the assistance of a person behind the wheel, whose task will be mainly to control the actions of the autopilot), the visibility of their navigation sensors (also based on radars) will become an extremely important aspect of safety.
BMW, a manufacturer of both automobiles and motorcycles, including the 2021 R 1250 RT – one of the first motorcycles to be equipped with radar – is well aware of the severity of this problem, and a recently published patent confirms that work is underway. The company’s designers, as is often the case, have spied on the solution in the environment. True, this time not in wildlife, but in marine navigation technologies.
Marine navigation technologies
The fact is that a very similar situation has developed in the sea not so long ago: there are also large metal objects-ships side by side with small plastic and composite ones. Here, of course, the issue of visibility is also acute, including visibility in the beams of radars, which are used for automatic and manual navigation much wider than on the roads. To solve it, radar reflectors (also known as reflectors or return ones) are used, which come in two varieties, active and passive. The idea of BMW passive radar reflectors was borrowed from sailors.
Small sea vessels are massively equipped with reflectors, and most often it is passive. These safety critical instruments are made from ordinary sheet metal, the elements of which are joined at specific angles to form volumetric reflectors that return the radar waves back to their source. BMW decided to use a similar design on their motorcycles.
Motorcycle visible on radar
Marine radar reflectors are quite large – 30 centimeters in diameter and more. Their motorcycle counterparts may be significantly smaller, but even small metal return units will be sufficient to reflect the millimeter waves of transport radars. The BMW patent application contains a sketch of a motorcycle equipped with a golf ball-sized return, which is structurally a miniature version of a ship’s radar reflector. Such elements, installed on the ends of the handlebars and on the wheel axles, make the motorcycle clearly visible in the radar beams from any angle, since they return the beam no worse than a large metal object.
The BMW patent suggests that, to minimize weight, the reflectors can be made of plastic coated with a metallization, and their arrangement allows them to simultaneously act as sliders, deforming in the event of falls or collisions. This feature, by the way, allows BMW to claim the uniqueness of its invention and separate it from the earlier Suzuki patent, which also describes passive radar reflectors installed on motorcycles.
Well, you and I, one way or another, will definitely have to learn to ride in a stream where cars are driven not only by people, but also by computers. And it’s nice that manufacturers take this fact into account and have already prepared solutions, albeit not the most beautiful ones, but simple and effective. Of course, such reflectors can be installed on earlier motorcycles, and even if BMW does not want to sell them as a separate product, the aftermarket manufacturers will certainly take the lead and release something similar, conditionally not violating the BMW patent.