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Efficient transport would see the most people moved in the fewest vehicles. Mini-buses are a fundamental missing component of that.



Why does an average bus journey in the EU emit more CO2 per passenger kilometre than a car of 4-people? Because buses with a capacity of 60-120 passengers are carrying an average of 12.7 passengers! That suggests that many bus journeys would be much more efficient if replaced by smaller mini-buses which can carry between 10-20 passengers. Where are the mini-buses in, for instance, the UK transport system? They are common in some countries - the main vehicle (carrying more than 4 passengers) in Ugandan cities, for example. As well as being more efficient for transporting smaller numbers of people, they do not require bus stops, and can much more easily vary their route to meet demand.

Ride-sharing apps have the perfect opportunity to introduce this missing, and greatly needed, link into the transport system of many cities. Because of their data on journeys taken by people (which could be combined with google data on journeys), they are able to flexibly design mini-bus routes that vary by time of day based on the past data (and knowledge on upcoming events e.g. festivals). The routes can be set in advance, but as passengers submit their journeys the optimum locations and number of stops can be calculated on the fly. This would undoubtedly make the system more efficient and therefore if well-implemented would result in less people needing to drive and own cars, less empty buses, and cheaper journey prices for mass transportation.

What concrete idea do you propose?

A forward-thinking ride-sharing app should develop a computer program to look at trends in passenger use and predict routes where a 10-15 seater vehicle could reach sufficient capacity to be more effective than cars or buses providing those journeys. Individuals using the ride-sharing app would be offered the option of a short walk if there was a nearby route.

Using the existing ride-sharing data to determine routes should make the journeys of that app more efficient and thereby over time reduce prices and attract new customers. However, the quickest way to attract new customers would be to look at journeys on heavily-congested routes being taken by customers in cars from data from a service such as google maps, and advertise the new scheme to those customers.

The obvious place to introduce this would be somewhere where the ride-sharing app is already in use, and where public transportation has a low efficiency. Interactions with city councils would be needed to put across the benefits of the extended service and gain permission. It is likely some mini-buses would need to be purchased and loaned to drivers, as they are likely not to own them currently. If the project was successful then this approach could be phased out as drivers saw the benefit of investing in a larger vehicle. Alternatively, the ride-sharing app could simply provide an app-based service for drivers of public or private companies that own a fleet of mini-buses.

There are examples of companies recently starting to see the potential for mini-buses, but the proposed ideas seem to include inefficiencies. Uber has started using mini-buses in Cairo but, as far as I can tell, they are implemented similarly to buses. In cases where there is only small demand on a route this may be useful. But it loses the potential for optimising stops along the route to match up with passengers, and it doesn't ultilise the fleet of mini-buses most effectively because it doesn't offer different routes at different times of day. Alternatively, there seem to be start-ups in some UK cities that are designing whole routes in response to instantaneous demand. It seems likely that this could lead to inefficient routes because either few passengers will be picked up, or routes will be long and unappealling to passengers. Such an approach would probably be better achieved with a regular car that could be shared by different passengers. 

The approach I've described sits somewhere between the inflexible, large-capacity option of buses and the highly-flexible, low-capacity option of cars. It can thereby find a niche where it offers new efficiency to travellers and the transport system. Other options, however, seem doomed to fail or only play a small role because they do not take advantage of the particular beneficial attributes of mini-buses.

Who will take these actions?

Any existing or new ride-sharing app could develop this. The first step is to use existing passenger route data to develop a program to predict effective routes for a new fleet of larger vehicles. New companies or city councils could do this using data from app-based map services.

The companies looking to run the operation would need to work with councils, businesses and local drivers to ensure a number of mini-buses were available to pilot the service.


What impact will these actions have on sustainability within Travel & Mobility?

It’s reasonable to think that a mini-bus carrying 10 people should be at least as efficient per passenger-kilometre as a small car carrying 4 people (~40 g CO2), compared to ~70 gCO2 for a bus (buses with fewer passengers being even less efficient). Conservatively, since the average number of bus passengers is 12.7, half of buses could be directly replaced by mini-buses, reducing emissions per passenger-kilometre of those journeys by at least 40%, and all bus travel by 20%. Due to the increased flexibility of the service it should be possible to replace a good proportion of car journeys (where the focus should be on car journeys with only 1-2 people). These journeys have the potential to reduce emissions per passenger-kilometre by 60-75%. If a third of car journeys could be replaced, then that would be a 20% reduction in emissions from journeys currently made by car. Given that that the transport sector has shown very little reduction in emissions compared to other sectors, a 20% reduction in car and bus emissions would be a significant step. On top of the emission reduction, the purchase of new vehicles would allow for rapid shift to an electrified system with the potential to run on renewable electricity. An additional benefit would be reduced congestion due to fewer cars.

About the team members

Declan Finney is a UK climate scientist who has, at times, stepped into public policy research with respect to climate change. He has previously produced a briefing on health and climate change in policy for the Scottish Parliament Information Centre, and has recently carried out analysis to demonstrate inconsistencies between UK airport expansion and net-zero emission targets. On a personal level, Declan has not owned a car for almost a decade, and as such has used the plethora of other modes of transport, mainly walking, cycling, buses and trains, with occasional taxis. He has spent much time getting frustrated with buses or lack of them, and thinking how inefficient they are when they often run empty. However, as someone happy to share transportation, taxis have never played a major part in his travel. This proposal is inspired by his own experience of the transport system.