Above and to the right is a plot of the average velocity as a function of the density of cars, obtained from a simulation of the original Nagel–Schreckenberg model. In the deterministic limit, p = 0, the velocity is constant at the maximum velocity (here 5) up to a density ρ = 1/(maximum velocity + 1) = 1 / 6 = 0.167, at which point there is a discontinuity in the slope due to the sudden appearance of traffic jams. Then as the density increases further, the average velocity decreases until it reaches zero when the road is 100% occupied. When p = 0.3, and so there are random decreases in velocity, then at low densities the average velocity is of course slower. However, note p > 0 also shifts the density at which jams appear to lower densities – traffic jams appear at the knee in the curve which for p = 0.3 is close to 0.15, and the random decelerations round off the discontinuity in the slope found for p = 0 at the onset of traffic jams.