Tutorial Lane Occupancy

Main Page > Tutorials

Follower Density Follower Density is the density multiplied by the percent followers and is a more appropriate reflection of quality of driving conditions on two lane highways  Follower Density  is calculated from the Link_Lane_Detector output file to match the Average Headway given in Detector Aggregate output file

Take note of warm-up time and simulation time, as this will be needed later
 * Run simulation in SwashSim

To Run R Script
 * Set working directory to location of SwashSim output files
 * Input Link_Lane_Detector file that you would like to determine Follower Density for
 * Input Warm-Up time in seconds
 * Input Simulation time in seconds
 * R will output Follower Density that matches values in Detector Aggregate File

Calculations in R,
 * Filters out data in warm-up time
 * Count of vehicles in simulation is calculated
 * Count of vehicles in a following state is calculated (vehicles with a headway of 2.5 seconds or less)
 * The ratio of following vehicles to total vehicles within simulation is calculated
 * AverageSpeed is calculated by taking the mean of the given speeds
 * The simulation duration is then converted to an hourly measure and divided by average speed
 * Follower Density is then calculated by $$ \frac{Follower Count}{SimVehicleCount} \times SimVehicleCount \times \frac{(3600/SimulationDuration)}{AverageSpeed}$$

Lane Occupancy