How (round-trip) Carshare can ‘drive’ change in Cities

The future of mobility is an internationally hot topic. New Zealand has several ride share, e-scooter, bike share, and car share operators. Twitter and council chambers around the country have all debated the value these modes bring to a city.

It is often hard to keep up with all the new and quickly changing mobility movements – especially in car share. For example, there are three very different modes under the car share umbrella; peer to peer, round-trip, and free-floating. Despite using the same term ‘carshare’, the impacts and benefits delivered to the city and community couldn’t be more different.

  • Peer to peer carsharing such as YourDrive is when a private individual rents out their car to another user – It’s the Airbnb of rental vehicles. Peer to peer car-sharing is generally regarded as a rental car and left out of car share policies.
  • Round-trip carsharing such as Cityhop, is when a user books a vehicle from a dedicated location and returns the vehicle to the same location when finished. Round-trip is the largest and longest operating model worldwide.
  • Free-floating carsharing is similar to a Lime Scooter, you opportunistically unlock the closest one to you, and when finished, leave it within a specified homezone. Free-floating (being trialled by Mevo in Wellington) is the new model on the block, however research suggests it cannibalises public and active transport modes and doesn’t bring any other benefits to a city. Its nick name is self-drive taxi.
  • Round-trip car share is the great tool for a city wanting to reduce car ownership, reduce vehicle kilometres travelled, and increase modal shift. It’s estimated that every $1 invested by the City of Sydney into round-trip car has returned $6.16. Mobility futurist Tim Papandreou goes as far to say, “round-trip car sharing is the only proven tool that can change the congestion situation and create the drop needed in car ownership”. Many free-floating operators claim the same benefits, but as you will see the below the data and research does not support their claim – and they are a wolf in sheep’s clothing.


  • Round-trip car sharing is a great addition to a city and its mobility goals
  • Free-floating car share cannibalises active and public transport…let’s look into the data

1. Reducing vehicle ownership

The general finding is that every round-trip carshare vehicle removes 9-15 privately owned vehicles off the road. Some free-floating operators claim similar benefits – but these are unfounded.

In a German case study comparing round-trip and free-floating car share members there was a staggering difference in vehicle ownership behaviour;

Figure 1: Car ownership behaviour after joining car share clubs
The below data was reported in a German Case study of 1,122 car sharing customers

Similar findings were reported in a Vancouver study into local operators;

Figure 2: Vehicles per household prior and after joining a car share program in Vancouver.

Auckland Transport has conducted two surveys on Cityhop members, one in 2014 and one in 2018. It was interesting to see the global data and trends reflected locally. The survey data indicated that 38% of Cityhop households in in 2014, and 33% in 2018 had reduced the number of cars owned or now lived without a car! If we assume the respondents are representative of the entire member base, that would equal between 1200-1500 private vehicles off the road.

Figure 3: Cityhop members private car ownership behaviour
The below data is taken from Auckland Transport’s 2014, and 2018 survey of Cityhop users

2. Modal Shift

Getting people out of cars, and into public and active modes is a goal of every major city. Car share is an important tool for cities to encourage mode-shift, as it gives people another transport option just in case (cough train ‘signal issues’). Because of this, round-trip car share has been found to increase public and active transport use internationally.

On the other hand, it becomes apparent that free-floating car share cannibalises public and active transport modes. In cities such as Vancouver, free-floating car share vehicles are described as ‘drive-yourself-taxis’, as users simply drive themselves instead of walking or waiting for public transport.

Figure 5: Public Transport Behaviour: The below research was carried out on 1,122 carsharing customers in Germany .

Similar trends are seen in other Cities internationally. In Switzerland free-floating car share members walk, bus and train less after joining. On the other hand, round-trip car share members walk, bus and train more after joining.

Figure 6: Perceived change in mode use through the car-sharing membership (free-floating N=337, station-based N=380)

Looking at the international data, it becomes evident that free-floating car share cannibalising active and public transport modes. Other examples can be found in the America’s, such as Seattle. Here members of the free-floating Car2Go reduce active and public transport use after joining (Figure 7).

Figure 7: Transport modes of Car2Go (free-floating) members since joining

The data from around the world demonstrates the same behaviour – free-floating car share undermines the public and active transport investments a city makes. When a user thinks it is more convenient to drive a car over active or public transport, they replace the mode with a vehicle trip.

The opposite behaviour is seen in round-trip car share members – they increase their active and public transport use. This is corroborated locally in Auckland, where Cityhop (round-trip) members reported a significant increase in both active and public transport use after joining (Figure 8, 9).

Figure 8: Cityhop (round-trip) members use of other transport options since joining

3. Reduced Vehicle Kilometres Travelled (VKT)

Reducing vehicle kilometres travelled is another important goal for a city – and another benefit round-trip services provide. With less VKT, there are fewer cars on the road (congestion), fewer road accidents (trauma), and fewer emissions produced (CO2-e) – which all provide a value back to a City.

Round-trip car share users from the City of Sydney reported to travel 2,000km less after joining . The Philip Boyle report into The Impact of Car Sharing Services in Australia calculated that every VKT reduced provided $0. 307 of benefits to a city, as seen below;

Figure 9: Summary of benefits and values related to lower VKT See, The Impact of Car Share Services in Australia

If we assume that Cityhop car share members have the same behaviour as GoGet (Australia’s largest operator) car share members, every year these members:

You can probably guess that if a free-floating car share service doesn’t reduce car ownership, and doesn’t increase public/active transport, that it won’t reduce VKT. And the data would suggest that you are right. When users replace public and active transport modes with a vehicle journey, the mode is creating vehicle kilometres travelled – not reducing. Figure 10 highlights that users don’t report any significant change in driving behaviour. Research comparing free-floating members with non-car sharing members found very little difference in driving behaviour. Figure 11 details how free-floating members had a similar number of trips, distance travelled, and trip duration as a private vehicle! Not the behaviour a City would want to encourage.

Figure 10: Perceived change in mode use through the car-sharing membership (free-floating N=337, station-based N=380)
Figure 11: Free-floating and non-car sharing users compared (Free floating N=109, Non-car shar users N=95)


The Philip Boyle report into The Impact of Car Sharing Services in Australia described each round-trip car share vehicle as providing $48,000 of net value to the City of Sydney – a $6.16 return on ever $1.00 of invested (Figure 12). How many local transport initiatives can boost a positive return like this?

Figure 12: Summary of Economic Analysis See, The Impact of Car Share Services in Australia:

Round-trip car share has been proven locally and internationally to be a great tool for cities wanting to get people out of their private car, and into public and active transport. To date, these services have received minimal support from local government unlike the city of Sydney. It seems counter intuitive to reduce cars and congestion by adding more cars – but round-trip car share services like Cityhop work!
The only thing restricting a precipitous drop in congestion and car ownership from a much bigger car share service is transport policy.

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