Volkswagen is working on headlights that can project light signals onto the road. The headlights communicate the intentions of motorists and self-driving cars with fellow road users and pedestrians.
Eye contact plays an important role in traffic. For example, by making eye contact, pedestrians can assess whether a motorist has seen them and can, for example, brake in time for the zebra crossing. However, it is not always possible to make eye contact. For example, drivers are less visible in the dark or sunglasses may obscure a motorist's eyes. In addition, the first (semi)-autonomous vehicles are expected to be introduced on public roads in the foreseeable future, which no longer have a human driver and with which eye contact is therefore not possible.
Micro-pixel HD headlights
Volkswagen wants to tackle this problem using 'micro-pixel HD headlights'. These headlights are capable of projecting information in front of the car onto the road to enhance road safety. Think about the vehicle's direction of travel.
The projections can also be used to assist motorists in driving the vehicle. As an example, Volkswagen mentions a system where the headlights project stripes on the road in front of the car to indicate how wide the vehicle is, including any trailer. This helps drivers estimate how far they are from the lane markings, which can increase safety on narrowed lanes during roadworks, for example. The system automatically adapts to curves.
30,000 pixels per LED chip
The micro-pixel HD headlights are based on a trio of micro-pixel LED chips. These chips each contain 1,024 pixels, spread over an area of just 4 by 4 mm. The 3,072 pixels counted by the three chips together can be controlled individually. Each individual LED chip is square and has an area of about 16mm2. As a result, these chips also project light in a square pattern. However, for the sake of driving comfort, light in cars is projected in a rectangular shape with a 3:1 ratio. Volkswagen therefore deploys an optical system to transform the square projection into a rectangular projection. This process currently makes the headlights relatively complex. However, Volkswagen expects the use of rectangular LED chips to simplify the design of optical systems in the future.
The three LED chips in the HD headlights currently contain a total of 3,071 pixels. However, Volkswagen expects that the technology can be further developed and that the LED chips could eventually contain 30,000 pixels apiece. In practice, this would mean that the micro-pixel HD headlights could offer the same resolution as HD-LCD headlights, while consuming significantly less energy.
Showing warning symbols on tail lights
In addition to headlights, Volkswagen is working on interactive rear lights on which warning symbols can be displayed. These symbols will warn rear-facing motorists of danger, such as the onset of a traffic jam or sudden braking. Like micro-pixel HD headlights, these tail lights can project symbols onto the road. Among other things, this can be used to project the vehicle's route onto the road during reverse parking and inform bystanders accordingly.
Both the headlights and tail lights are being tested by Volkswagen at a centre of excellence at its plant in Wolfsburg, Germany. This involves using a tunnel 100 metres long, 15 metres wide and 5 metres long to carry out simulations. These include simulations to test how pedestrians experience the lighting and light signals or or to visualise the effectiveness of the lighting.
Other manufacturers are also betting on light signals
Volkswagen is not the only party looking to use light signals to improve road safety. Mitsubishi Electric, for instance, is also working on the Safe and Secure Lightning system. This system projects signals on the road and screens on the car to warn pedestrians and fellow users of the driver's intentions. Like Volkswagen's system, the Safe and Secure Lightning system can, for example, use projected arrows on the road to indicate the direction of travel if reversing. Mitsubishi Electric expects the system to be of interest to both traditional cars with human drivers and autonomous vehicles.
Ford also experimenting with light signals. The company previously conducted an experiment with a light bar mounted on the top of the windscreen of a Ford Transit Connect. This system is specifically aimed at autonomous vehicles; during the experiment, the vehicle was driven by a human driver who was invisible from outside the vehicle.
Vision URBANETIC
Mercedes-Benz Vans earlier this year presented Vision URBANETIC, an autonomous and electrically powered concept vehicle. This prototype can be easily configured as a passenger transport vehicle or a goods van thanks to an interchangeable bodywork. The Vision URBANETIC features a large screen at the front, which uses symbols to inform pedestrians that their presence has been registered. In addition, hundreds of small light units have been deployed on the side of the vehicle to create shadows of people in close proximity to the vehicle. This helps improve the visibility of these persons and thus improve road safety.
Finally, early this month, Ford called for standardising communication from autonomous vehicles to fellow users and pedestrians worldwide. By communicating in a uniform way, the vehicles' intentions are easier to recognise, which Ford says helps to grow trust in autonomous cars. Indeed, autonomous vehicles can draw completely different conclusions from humans based on the same information, which can make their behaviour unpredictable.
Author: Wouter Hoeffnagel
Source: Volkswagen (pictured)
Source: Ford
Source: Mercedes-Benz Vans
Source: Mitsubishi Electric
