Kinetic speed vs. Consumer speed

The Austrian philosopher Ivan Illich, a critic of the modern society habits, was one of the first thinkers to establish the so-called consumer speed or virtual speed concept. He wrote in his book Energy and Habits published in 1974:

The model American male devotes more than 1600 hours a year to his car. He sits in it while it goes and while it stands idling. He parks it and searches for it. He earns the money to put down on it and to meet the monthly installments. He works to pay for gasoline, tolls, insurance, taxes, and tickets. He spends four of his sixteen waking hours on the road or gathering his resources for it. And this figure does not take into account the time consumed by other activities dictated by transport: time spent in hospitals, traffic courts, and garages; time spent watching automobile commercials or attending consumer education meetings to improve the quality of the next buy. The model American puts in 1600 hours to get 7500 miles: less than five miles per hour [the consumer speed]. In countries deprived of a transportation industry, people manage to do the same, walking wherever they want to go, and they allocate only 3 to 8 percent of their society's time budget to traffic instead of 28 percent. What distinguishes the traffic in rich countries from the traffic in poor countries is not more mileage per hour of lifetime for the majority, but more hours of compulsory consumption of high doses of energy, packaged and unequally distributed by the transportation industry.

Kinetic speed

It is known by classical mechanics that the average kinetic speed  of an automobile and its passengers is simply the amount of space the car travels, divided by the elapsed time, i.e.:

where  is the distance travelled by the car and  is the travelled time, i.e., the time elapsed during the travel.

Consumer speed

Though, to access the consumer speed, we must sum the amount of time, the car owner strictly allocates to work to afford such travelled distance. Then the consumer speed  is:

where  is the time the driver needs to work, to afford doing that travelled distance  using such car.


James (an example), a common car owner and driver who takes his car to get to work, spends totally (standing and running costs) on his car an average of €5000 per year. Considering James just uses his car to get to work and that one year has around 250 business days, James pays on average €20 per working day to afford his car. Consider the James' average net salary is €10 per hour; then James needs to work 2 hours per day just to afford his mean of transport to get to work, time strictly allocated to pay his car bills.

If he lives 20 km away from his workplace and he gets there in half an hour, then he makes 40 km per day during one hour (round trip). His kinetic average speed would then be:

Though, James needs on average 2 hours per day just to afford his car, working time budget strictly allocated for paying his car bills, so his consumer speed would be:

just 1/3 of his kinetic speed.