Autonomous Vehicles are Not New
In the last year, unmanned cars have made the headlines throughout the world, and the idea that cars could be driven solely by computers came as a shock to many. The reality is that driverless vehicles have been around for some time, both in railway and PRT operations, and analyzing how driverless technology has been implemented there should help understand how this technology will be brought to market and the hurdles that the automotive industry will face.
Considering key success factors from the two industries with driverless experience, we anticipate a continuum of new technologies that will be introduced to the market before any car achieves absolute autonomy. Although some manufacturers and car specialists envision driverless cars as fully autonomous solutions, they will never be as independent as driven cars are today. The reason is quite simple: they will rely on vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication.
It is less exciting to picture a system approach rather than a solution mimicking today’s reality, where all intelligence is onboard, in the driver’s brain. Skeptics of a system approach will argue that the fleet of 23 Lexus Google cars that didn’t have V2V or V2I capacities was able to run more than 1.7 million miles. That’s true, but they did suffer 11 accidents.
Even though none of these accidents could be attributed to Google’s driverless technology, but human errors of other drivers, if you believe, like I do, that 100% accident-free must be the norm for driverless cars, this isn’t good enough. To be more accurate, the industry will need to meet the stringent requirements of a 10-9 failure rate for critical elements, as it is the standard for driverless trains.
The point is that the only way to avoid systematic rear-end or lateral collisions is to get fore or immediate knowledge of deceleration from the car in front or from a car changing lane and to apply safety principles guiding all movements.
Vehicular Ad Hoc Network (VANET)
VANET technologies, combined with proper software, should take care of communication requirements. For safety principles, the automotive industry can look to the railway industry, which has been dealing with safety issues for more than 200 years. Railway engineers have come up with four general principles and thousands of technologies that ensure that these principles are systematically obeyed:
- Block interlocking: under normal circumstances, sections of railway – known as blocks – can allow only one vehicle at a time. Thus, vehicles cannot collide with each other if they are not permitted to occupy the same section simultaneously. However, this is only a certainty if vehicles are spaced far enough apart to ensure that they cannot collide, taking into consideration factors such as speed, braking time, and ramp.
- Block signaling: signaling to the following vehicle (with driver or unmanned) that no car is in that section.
- Integrity: Even though a vehicle might have left a block section, there is always the possibility that a trailer could have separated from the head vehicle, which is especially crucial for long freight convoys. Besides the “carriage integrity” principle, which is critical for the success of platooning technology, railways face the track integrity issue, which also applies to cars (e.g., potholes, rocks).
- Interoperability: Although safety concerns don’t drive the decision to make a system interoperable, it is often influenced by political vision or economic choices, which have safety implications. Once the decision is made to integrate various elements of a system, these elements need to work together safely. Both physical and conceptual interoperability are necessary to integrate multiple networks.
Lessons to be Learned
The automotive industry will need to make these principles its own with a few adaptations, creating new technologies and a multi-billion-dollar market by the same token. Car manufacturers will also have to rely on international standards with stringent homologation processes – something they have not been good at in the past.
