A passenger transportation system for rural and suburban areas, based on the combination of a new built low-cost route network and cabin motorcycles, operated automatically without interaction with conventional road traffic: On one hand, separation from human steered, fast moving and heavy vehicles reduces technological complexity, weight, costs and energy consumption, on the other hand, construction effort for the new infrastructure is kept low thanks to low axle load and very narrow lanes.
More than a self-driving car: eco-efficient accessibility where you really need it
Proposals of new technologies for passenger transportation usually focus on densely built-up urban areas, where ecological and capacity-related problems of car traffic are most visible. In contrary to this, the concept of 2-wheel Personal Rapid Transit (2-wheel PRT) is intended for rural and suburban areas, where greenhouse gas emissions from transport and accident rates are even higher, than in cities and until now, there are no economically feasible high-quality solutions of public transport.
The 2-wheel PRT transportation concept is based on self-driving cabin motorcycles, a technology that seems feasible after some prototypes and design drafts published recently (Yamaha Motobot, Cyclotron). The key advantage of an autonomous 2-wheeler is the ability to ride on an extremely cheap road infrastructure: the paved roadway surface can be even more narrow than the vehicle itself, low axle load means low maintenance costs and low vehicle height makes it easy to construct over- and underpasses. Under these favourable circumstances, it is realistic to realise a new, additional road network specifically for these vehicles (at least outside built-up areas).
Automated vehicles, running on their own dedicated network have two significant advantages compared to self-driving vehicles in mixed traffic with ordinary, human-driven cars: First it is technologically less complicated, because the vehicle steering system can rely on car-2-car and car-2-infrastructure communications and doesn’t have to take into account the individual behaviour of human steered vehicles, cyclists or pedestrians. Therefore, the technical and economic feasibility of completely automatic operation (SAE Level 5) becomes much more realistic. Second, there is no risk of collisions with fast moving, heavy vehicles caused by human failure on their side. This gives the opportunity to reverse the weight spiral: If there is no need to survive a crash with a heavier vehicle at high speed, a more lightweight car body construction is possible. Less car body weight means less power output required, less motor and battery weight, leading again to less car body weight. As all vehicles run at the same speed (no overtaking necessary) and backbone routes are grade free and bypass built-up areas, the vehicles run long distances at constant speed. Effectively, the calculated energy consumption is about 4-5 kilowatt-hours per passenger-km (7 kWh per passenger-mile), that’s the half of existing electric compact cars and comparable to a car consuming about 1,15 – 1,3 l diesel fuel per 100 km (0,5-0,55 gallons per mile).
The 2-wheel PRT concept intends the use of two types of vehicles in a sharing system. One vehicle type is designed for a single user, the other one accommodates a wheelchair or two adults or one adult and several children depending on their age. As you always use an appropriate vehicle size and empty vehicles can be redistributed automatically, their capacity is utilized very well and there is low demand of parking area. The low driving resistance results not only in low electricity consumption, but also low required engine output and battery consumption, reducing the demand of rare earth elements and other resources, but of course saving costs too. Thus, in contrary to self-driving cars on ordinary public roads, 2-wheel PRT promises not only more eco-efficiency, but also affordable mobility regardless of driving license and car ownership.