Passenger car equivalent (PCE) or passenger car unit (PCU) is a metric used in transportation engineering to assess traffic-flow rate on a highway.
Traffic studies and/or analysis must be done to obtain the number of trips, which shall then be converted to PCUs based on the above standards.
However, the PCU values derived from the density method are based on underlying homogeneous traffic concepts such as strict lane discipline, car following, and a vehicle fleet that does not vary greatly in width.
Many methods exist for determining passenger car units (PCUs).
For example, in the UK in the 1960s and 1970s, bicycles were evaluated thus: This road-related article is a stub.