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Passenger car equivalent (PCE) or passenger car unit (PCU) is a metric used in transportation engineering to assess traffic-flow rate on a highway. [1]A passenger car equivalent is essentially the impact that a mode of transport has on traffic variables (such as headway, speed, density) compared to a single car.
In the study of traffic flow theory, the flow-density diagram is used to determine the traffic state of a roadway. Currently, there are two types of flow density graphs: parabolic and triangular. Academia views the triangular flow-density curve as more the accurate representation of real world events. The triangular curve consists of two vectors.
Density (k) is defined as the number of vehicles per unit length of the roadway. In traffic flow, the two most important densities are the critical density (k c) and jam density (k j). The maximum density achievable under free flow is k c, while k j is the maximum density achieved under congestion. In general, jam density is five times the ...
The K Factor also helps calculate the peak-to-daily ratio of traffic. K30 helps maintain a healthy volume to capacity ratio. [3] K50 and K100 will sometimes be seen. K50 and K100 will not use the 30th highest hourly traffic volumes but the 50th or 100th highest hourly traffic volume when calculating the K factor.
Level of service (LOS) is a qualitative measure used to relate the quality of motor vehicle traffic service. LOS is used to analyze roadways and intersections by categorizing traffic flow and assigning quality levels of traffic based on performance measure like vehicle speed, density, congestion, etc.
Annual average weekday traffic (AAWT) is similar to AADT but only includes Monday to Friday data. Public holidays are often excluded from the AAWT calculation. Average summer daily traffic (abbreviated to ASDT) is a similar measure to the annual average daily traffic. Data collecting methods of the two are exactly the same, however the ASDT ...
Three parallel escalators; the direction of the middle escalator can be changed to double capacity in one direction (↑↑↓ or ↑↓↓).. Many public transport systems handle a high directional flow of passengers— often traveling to work in a city in the morning rush hour and away from the said city in the late afternoon.
Since the density is constant along the characteristics, if one knows the cumulative curves A(x0,t0) and flow q(x0,t0) at boundary, one can construct the three-dimensional surface (A,x,t). However, if characteristics intersect, the surface is a multi-valued function of x,t based on the initial and boundary conditions it is derived from.