Some people need to commune for work or personal reasons regularly, but cannot afford their own car.
Currently, taxis, public transport and lift services like Uber do cater for this group of people, but they still aren't as efficient and convenient as having your own car. They either only travel to fixed destinations at fixed times (trains/busses) or require you to wait to be picked up, charging you for the distance travelled, not allowing you to make quick stops along the way.
My idea is to have a car rental service that provides a vehicle for people who needs one for a short period of time.
This service would focus on commuters who need transport to more than one place within a day. So instead of renting a car at a fixed daily rate, or ordering a new uber or taxi after every stop, you'd be able to rent a car to use as you please for as long as you need.
A form of this model already exists for bicycles in South Africa. Up Cycles allow you to pick up a bicycle at any station, use it as you please and return it to a station when you are done.
You'd need to sign up to be able to use one of the available cars, meaning that the company would have all your necessary details for their insurance purposes. Then, when you need a vehicle, you can simply pick one up by swiping your membership card. No additional paperwork would be required.
All vehicles will be fitted with GPS trackers and you will be billed according to the distance travelled / time that you used the vehicle for.
For this service to differentiate itself from normal car rental services, it would have to work out cheaper and be much more convenient. It isn't very difficult to rent a car nowadays, so the fact that you would simply have to swipe your card to pick up a vehicle might not be enough.
However, even though rental services do allow for short term leases, renting a car for less than a day is not their main area of focus and their prices tend to be quite expensive for shorter rentals.
Ways to stand out from competitors:
I can think of two ways to really differentiate the service from traditional car rental companies.
Bill customers per kilometer instead of according to the time the vehicle is in their possession. This way, people won't pay for the time that the vehicle is not in use. The problem with this is that the company loses money when the vehicle is standing still and someone else could have been using it. The solution to this problem leads to the second idea.
Create a geo-locating app that shows all idle cars in a customer's vicinity. That means you can drive the car anywhere and simply leave it there for the next customer.
Doing away with fixed drop-off points is the main component of this idea, but this comes with its own problems.
If a customer makes a mess in the car, or even damages it, there would have to be a way to make sure that the responsible customer can be identified. If four different people use a car throughout a day, it'd be difficult to pin point who should carry the cost for the damage.
In order to ensure that this does not become a problem, customers can act as the inspectors. Before you use a vehicle, it'd be your job to ensure that all external components are clean and not broken. If you encounter a car that is not in a good condition, you can report it and look for another vehicle. If you decide to use a car, all responsibility would fall on you as the most recent driver. (This would not include internal problems like issues with the engine, as that is difficult to access before driving)
To ensure that customers aren't driving the cars too far away from your main area of operations, pricing can be adjusted according to where in the city you are. If you drive out of a certain radius you will be billed on time, meaning that you can't simply leave the car in another city where the service provider does not operate.
Regional teams can easily collect cars at the end of a day/week, or customers can be incentivised to drop the vehicles at a depot after a certain time of day with return discounts. Meaning that if you use a car after 9 P.M and return it to the lot instead of just leaving it somewhere, you will get a discounted price.
You will need to have quite a large fleet of vehicles to ensure that options are always readily available, but I think that it could work in city centers and densely populated areas.