This article isn’t about the type of car we should buy according to our financial situation or that best suits our needs as individual or as a family,

whereas, the following article aims to analyse the element that always has been and still represent, in most societies, the core of the general mobility model, which, from many decades now, heavily shapes our entire lives and environment, especially within the urban area.

Technology is offering several types of innovative automobiles, which bet on the ecological factor (electric cars), and on safety (driver assisted or driverless cars), presenting them as “resolvent models” in the field of sustainability.

EV for blog VIS

Although, is it reasonable to consider the electric engine totally clean and perfectly integrated into the perspective of a liveable city? Is it sufficient to provide the car with some kind of braking device or with autonomous driving itself, to allocate the automobile as a “smart and safe vehicle”?

To answer these questions, is it possible to identify some essential criteria that are useful to evaluate how much an automobile is compliant whit the ecosystem, the city and the citizens:


Each car has an environmental impact that must be globally considered, starting with the retrieving of raw materials (actually even before, since the elaborate design process), until the disposal of the vehicle at the end of its life cycle.

Therefore, it is clearly not sufficient to take into account only the exhaust fume of a vehicle as the indicator of its level of pollution, just like it is not possible to consider null and void the polluting capacity of an electric vehicle just because it has zero-emissions.


Further to other phenomena of harmful powder and spoil production caused by frictional effects and oil consumption, the weight and the size of a vehicle play a key role in factory processes: they modify the amount of required materials and the production processes, not even counting the different amount of energy needed over the same distance travelled.

EV issues 1

EV issues 2


Our cities suffer from a major decay of the public spaces allocated for mobility. About the 80% of the total available area for the citizens is almost entirely occupied and blocked up by the invasive monopoly of the car-land, both circulating and stationary.
Also in this case, given the same number of vehicles on a certain urban area, the size of the cars can make a difference regarding the total encumbrance.

Cars take up space

In addition, it is essential to analyse a factor that can be defined as the “replacement rate”: the capacity of a car, properly used, to replace a certain number of other vehicles.
The “car-sharing” between two friends or colleagues that use togheter only one of their private cars alternatively to come and go from work, is an example. The replacement rate of systematic activity of this sort is approximately 1:2.
The replacement rate of a car in co-ownership among 4 families is 1:4, if the vehicle allows each family to renounce owning at least one private car.

A further circumstance is the “driverless car-sharing”, that must be managed by institutions or companies and that usually works through a mobile app. The standard-type service provides that the booked car arrives at an established time and place, picks up the client and once arrived at the destination it is already prepared to the next service.

In this hypothesis the rate of replacement would be very high, it would be about from 1:20 to 1:50, since each shared driverless car could replace the production, the ownership and the encumbrance of 20 to 50 traditional private cars.



The safety requirement of an automobile can’t be referred only to factors like drive assistance devices or to the features of braking system and illumination.

In these cases it is not possible to estimate the main cause of road accidents, injury and mortality: the human factor. The evaluation is limited to the offensive potential (offence-rate).

The top level autonomous driving system itself, the one that doesn’t require any driver to control the vehicle, and that should have as a fundamental condition the protection of the safety of the passengers and of all the other road-users, has as a limit the programming parameters of computerized and telematic driving systems themselves.

It is fair to say that the offence-rate of a traditional human-driven car for its passengers and the surrounding subjects, it is proportional to the vehicle weight/dimensions and to its achievable speed. Likewise, the same index can be referred to driverless cars through the more or less precautionary parameters (e.g. urban speed) set by man within the programming software.

Thereby it is possible to discern the most dangerous vehicle, the one that is the biggest, the fastest and is human-driven, from the safest vehicle: the one that is small, lightweight and provided with a driverless system set on the maximum safety buffer, that goes through all the intermediate configurations.



It is noticeable that some of the factors of the vehicle’s constructive parameters indeed belong to the three categories previously listed. These are the weight and the dimension of the vehicle, in addition to the maximum speed that a car can achieve.

It is important to seriously have a thought about the meaning of use a 2 tons car to move 75 kilograms of human being, and it is also essential taking into account all the topics that have been already presented: the precarious condition of the environmental balance, urban congestion and, of course, road danger.

Regarding the concept of “safe speed”, the core position is occupied by the driverless systems, as a parameter set by man based on the utmost possible restraint, especially in urban areas, this is the context that is considered the most appropriate for driverless technology to take place. Likewise, is possible to introduce technologic solutions designed to control and set up in real-time the maximum speed rate in human-driven cars.



With the combination of the 4 main criteria that has been previously explained is it possible to create a multicriteria-matrix useful for the evaluation of various car-types that possess different mixes of the 4 criteria. The evaluation is based on 3 parameters:


By assigning a score from 0 to 8 according to the worst or best evaluation of each aspect that has been observed, is it possible to obtain a classification that goes from the worst car-type, the one that is large-sized, fast, based on fossil fuels and non-shared, which is the most commonly used; to the car-type to which both industries and decision-makers, in addition to the community, should aspire in order to introduce this form of transport as a part of the wider picture of the mobility-universe. This is the only vehicle compatible with environment, cities and citizens, and this has to be small, lightweight, electric power-driven, with a high replacement rate, shared and driverless.

If one is looking for the car-type that bets only on electric engine or on driverless systems, they are going to be far down the ranking, respectively they are the second-to-last, and the last. To corroborate that the field is dramatically filled with false myths and urban legends.

(Thanks to Marco Martens for Multicriteria Matrix idea)

EN matrice multicriteri QUALE automobile settembre




We must never forget the basic vision that supports the sustainable structure of mobility, the urban one especially.

The current modal share is sobering unbalanced towards an (ab)use of powered private vehicle that, in city like Rome, for instance, reaches the devastating measures or 70% of trips.

The new concept of car, as we rapresent it here,  has to be functional to an overall remodulation with the goal the following situation, compatibly with each single territorial reality:

40% public/ collective transport;

30% pedestrian and bicycle shift;

20% light, electric, slow, shared and driverless on demand means;

10% residual traditional mobility, expecially for emergency, security and safety.

Alfredo Giordani                                                                                                                                    Rete #Vivinstrada



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