Advantages of 2-wheel PRT

Energy efficiency

The electricity consumption of 2-wheel-PRT of about 4,5 kWh/ 100 pkm (passenger-km) [7 kWh per 100 passenger-miles] is about 1/4 of an electric sports car, the half of an electric compact car or 1/3 of electric public transport. According to the EU electricity mix, the standard vehicle (occupancy rate 0,8 including redistribution of empty vehicles) resp. the enlarged vehicle (occupancy 1,4) have the same CO2 emission as a combustion engine driven car consuming 1,15 resp. 1,3 l diesel fuel per 100 km [0,5 - 0,55 gallons per 100 miles] at an average occupancy of 1,4 passengers.
Assumptions and references for energy efficiency calculation

Why is 2-wheel PRT so energy efficient?

Service Performance

  • Mobility for all: Accessibility without own car and driving license enormously increases the mobility of a big part of population in rural and suburban areas which is nowadays dependent on poor public transport connections or help from relatives or friends

  • Travel time can be used well for different purposes (working, reading, sleeping...) because of autonomous driving and more privacy than in public transport

  • Similar travel times as in conventional rural car transportation (travel speed rather higher than average of conventional roads out-of-town and in-town)

  • no stress from driving and interaction with other drivers

  • increased flexibility and shorter travel times compared to rural public transport:
    • No waiting time for next scheduled bus or train
    • Always direct connections instead of detours and changing between different public transport lines
    • No intermediate stops

Less technological effort than autonomous driving on public roads

An isolated system of self-steering vehicles on their own network can rely on car-to-car and car-to-infrastructure communication or use specific navigation marks as e.g. RFID chips or radar reflectors. The vehicle runs only on a high-quality road surface, there is no need for any off-road capabilities. The vehicle knows size and behavior of the other vehicles and the network is completely grade-free, avoiding difficult road configurations. All vehicles within the same road section run at the same speed, there is no need for overtaking. This makes the vehicles safer and cheaper and really autonomous operation becomes feasible, while the use of autopilot systems on public roads is still restricted to a low-density motorway network and presence and attention of a driver with a valid driving license.


As a first approximation concerning economical feasibility, total costs of 2-wheel PRT were calculated for a suburban and a rural case study region in Austria. Inevitably big uncertainties concerning a variety of input values were considered by calculating separately with optimistic, medium and pessimistic assumptions, leading to a wide range of results:

  • Following the optimistic calculation, the average costs of a passenger-km is about 0,05 EUR [0,1 USD/passenger-mile]. In this case, cost-covering prices for 2-wheel PRT would be competitive compared to conventional public transport as well as to conventional cars, even if considering only perceived variable costs as fuel or tickets and without consideration of higher service quality.

  • The standard calculation leads to costs of around 0,11-0,12 EUR/Pkm [0,21-0,23 USD/pass-mi]. This is slightly more than the real variable costs of an individual compact car (including maintenance and mileage-dependent depreciation), but still by far less than total costs of such a car per passenger-mileage. Compared to public transport, it would be cheaper to move people by 2-wheel PRT than by bus or train, but cost-covering 2-wheel-PRT fares would be anyway more expensive, than the average passenger-km travelled by public transport at a price, that is strongly influenced by subsidies for comprehensive public transport networks and cheap tickets particularly for commuters. According to this calculation, 2-wheel PRT would be economically feasible without additional public expenses, but in order to offer similarly cheap transportation as today's public transport, a part of the public transport subsidies must be shifted to 2-wheel PRT.

  • The result of the pessimistic calculation is 0,28-0,31 EUR/Pkm [0,54-0,60 USD/pass-mi], corresponding roughly to the total costs per mileage of a conventional compact car. From the point of view, that there is no more necessity to own a car and that travelling becomes more convenient thanks to autonomous operation, this is still competitive with conventional cars, but it is significantly more expensive, than the average total costs of public transport in Austria. In this case, 2-wheel PRT can replace public transport only in those areas, where public transport works particularly inefficient: In such a case, current public transport subsidies per usage (EUR/Pkm) can be locally much higher or the drastical increase of service quality may lead to higher willingness-to-pay for 2-wheel PRT instead of public transport.
Assumptions and references for cost calculation

Proportionately to the wide range of input values, the share of route infrastructure costs, representing the most specific disadvantage of 2-wheel PRT, is between 6% and 27% of the total costs. Considering the cost-reducing effects of the separation from conventional traffic in terms of less required sensor technology and the spiral of passive safety, weight and engine output, these additional costs seem to be justified at least when applying the optimistic or the standard calculation.