Martin Randelhoff deals with a topic in the magazine "Zukunft Mobilität" (Future Mobility) which has the potential of becoming increasingly important in the future. The topic is about the problem of how ridesharing systems can become a mobility solution in rural areas, supplementing public transport.

For public transport providers, there’s a "critical mass" problem in rural areas – namely, there is neither sufficient supply nor sufficient demand to justify significant financial expenditure. At the same time, the age demographics of people in rural areas (with less school-age children, but more pensioners) has a strong effect on decreasing rural population density. Classical bus traffic routes simply cannot be performed cost-effectively, particularly in the early morning, in the late evening or at night. This could be the reason why ridesharing options by private cars and thus, ridesharing platforms, may play a future role. 

Randelhoff believes that, in spite of the above difficulties in relation to public transport, there is no lack of capacity – that is, of individuals actually requiring transport - since many private cars are permanently on the roads, in many cases with only one person in the car. This represents a large, untapped capacity reservoir. The main problem is how to achieve a congruence between the routes taken by car owners and the transport needs of their potential passengers, especially if round trips are demanded and long detours are to be avoided. 

This topic has been studied in Greater Los Angeles by a research team (Tsao and Lin). They found that employment density, commuter distance, as well as ridesharing distance, are crucial factors. Obviously, the ridesharing options decrease with increased ridesharing distance. This is because the probability of requiring large detours would also increase. Flexibility can be achieved by dynamic routing, with the passengers being collected along the way. If matching algorithms for source-target-ridesharing were to be applied, they could detect much more matching of supply and demand. 

In addition to spatial-geometric questions, individual preferences also play a role. These preferences can further reduce the match between supply and demand. An example of the factors mentioned in this context is the level of trust between the parties involved in such a personal space as is found in a carsharing journey. Trust is not such a problem in terms of carpooling amongst colleagues or neighbours, because this is usually established over time within a stable social environment. On the other hand, dynamic ridesharing reduces the options, because of this issue of personal trust when the individuals don’t know each other. Also, gender plays an important role. Men and women would share a trip with a female driver, but women are less willing to share trips with male drivers or male passengers. 

Because of the above-mentioned issues concerning supply/demand matching and personal preferences, it is doubtful whether ridesharing is an option which can sufficiently resolve the mobility problems in rural areas. Thus, the solo car use in an owned vehicle will regularly be preferred due to "perceived" higher safety and better comfort. However, carpooling with colleagues/neighbours, where people know and trust each other, can be a supplement. Apart from these options, the professional trip (e.g. taxi) as a supplement to public transport will be preferred to the alternative of solutions being offered by private drivers. 

Source: "Ridesharing in ländlichen Räumen – ein Baustein für die Mobilität auf dem Land?"