Efficient Use of Highway Capacity Summary
Report to Congress
Figure 35. Graph. Flow Impacts of Speed Harmonization—Germany.
Two side-by-side graphs comparing speed flow density curves on a facility
with and without speed harmonization. On both graphs, the flow q (vehicles/hour/lane)
and the y axis is speed v (km/h). The graph on the left — without
speed harmonization — indicates a typical speed flow diagram where
the flow begins to drop off significantly where the speed is 100 km/h
and the flow is 100 vehicles/hour/lane. The distribution of points on
the graph is fairly uniform until the speed drops to 40 km/h. The graph
on the right — with speed harmonization — differs in that
the majority of points on the graph are above 60 km/h. Fewer vehicles
experience a flow rate below that when speed harmonization is active.