R/nopass.R

In cartools: Tools for Understanding Highway Performance

#' \code{nopass} produces \code{t}, \code{u} and \code{x} for lead and following vehicles downstream of a bottleneck
#'
#' @return \code{brktrials} returns a data frame speed and location downstream of bottleneck.
#' @param veh vehicle, a number
#' @param nope is a data.frame of leading and following vehicles: time, speed and location data, a data frame
#' @param leff effective vehicle length in feet, a number
#' @usage nopass(veh, nope, leff)
#' @export
nopass <- function(veh, nope, leff) {
  if(is.null(dim(nope))) {
    fix          <- nope[c(4,5)]
  } else {
    hcrit        <- u <- x <- rep(NA, dim(nope)[1])
    for(j in 1:dim(nope)[1]) {
      u          <- as.numeric(nope[j,4])
      hcrit[j]   <- hsafe(u, leff)
    }
    hobs         <- nope[,3] - nope[,5]
    for(j in 1:dim(nope)[1]) {
      if(hobs[j] < hcrit[j]) {
        u.      <- as.numeric(nope[j,2])
        u[j]    <- nope[j,2]
        hfix    <- hsafe(u., leff)
        x[j]    <- nope[j,3] - hfix
      }  else {
        u[j]   <- nope[j,4]
        x[j]   <- nope[j,5]
      }
    }
    fix        <- data.frame(u, x)
  }
  return(fix)
}