  Connected automated vehicles (CAV), which incorporate vehicle-to-vehicle
(V2V) communication into their motion planning, are expected to provide a wide
range of benefits for individual and overall traffic flow. A frequent
constraint or required precondition is that compatible CAVs must already be
available in traffic at high penetration rates. Achieving such penetration
rates incrementally before providing ample benefits for users presents a
chicken-and-egg problem that is common in connected driving development. Based
on the example of a cooperative driving function for bottleneck traffic flows
(e.g. at a roadblock), we illustrate how such an evolutionary, incremental
introduction can be achieved under transparent assumptions and objectives. To
this end, we analyze the challenge from the perspectives of automation
technology, traffic flow, human factors and market, and present a principle
that 1) accounts for individual requirements from each domain; 2) provides
benefits for any penetration rate of compatible CAVs between 0 % and 100 % as
well as upward-compatibility for expected future developments in traffic; 3)
can strictly limit the negative effects of cooperation for any participant and
4) can be implemented with close-to-market technology. We discuss the technical
implementation as well as the effect on traffic flow over a wide parameter
spectrum for human and technical aspects.
