The article describes the work of Professor Michael Schreckenberger of the University of Duisburg and unnamed collaborators at the University of Cologne and Los Alamos National Laboratory.
Every car occupies one grid point.
Each grid point occupies at most one car. A car can have a speed of 0 - 5 grid points per time interval. A car with speed of less than 5 increases its speed by one unit in each time interval, until it reaches the maximum speed. If a car's distance to the car in front is d grid points, its speed is reduced to d -1 if necessary to avoid crashing into it. With a certain probability, in each time interval some cars slow down one unit for no good reason whatsoever.