Category : Miscellaneous Language Source Code
Archive   : OPAL140.ZIP
Filename : CRITICAL.OPL

{
CRITICAL.OPL - Critical Gap Example
OPAL - The Programmable DOS Shell
Copyright (c) 1986, The Software Factory, Inc.

This example OPAL program calculates the length of the critical gap, T
in seconds. T is a function of TH, the angle between the ramp anf highway
; D, the normalized length of the acceleration lane; and S, the ramp
factor.

S is zero for a tapered ramp, and one for a parallel ramp.
}

LET fldbar_ = '7m'
LET flddsp_ = '1m'

SCRCLR
SHOW "OPAL - Critical Gap On Ramp Example"
SHOW " "
SHOW "One of the factors used in evaluating the effectiveness of a ramp leading"
SHOW "to a highway is the Critical Gap. It is assumed that a driver waits on a"
SHOW "ramp until he estimates a time gap between successive vehicles which he"
SHOW "regards as sufficiently long for him to safely enter the traffic stream."
SHOW "This Critical Gap is a function of the angle between the ramp and the"
SHOW "highway, and the length of the acceleration lane."
SHOW " "
SHOW "The angle is entered in degrees."
SHOW "The acceleration lane is entered as a normalized length, i.e. /100"
SHOW " "
SHOW "A shape factor is available for Tapered or Parallel ramps"
SHOW " "
LET more=TRUE
DO WHILE more
SHOW " "
LET fldbuf_=' 10'
LET th=CONPROMPT(integer_,3,32,"Enter the angle between the Ramp and Highway: ",0,0,360)
IF th=0 THEN BREAK
LET fldbuf_=' 1.20'
LET d= CONPROMPT(real_,6.2,32,"Enter the normalized length of the Acceleration Lane: ")
IF d=0.0 THEN BREAK
LET fldbuf_='T'
LET type=CONPROMPT(string_,1,37,"Is the ramp Tapered or Parallel (T/P): ",1,"T","P")
IF type="T" THEN LET s=0
ELSE LET s=1
LET t=5.547+.828*th-1.043*d+.045*d*d-.042*th*th-.847*s
PRINT("%n%n*** Critical Gap=%6.2f secs.%n%n",t)

LET fldbuf_='N'
LET more=CONPROMPT(yesno_,1,32,"Run another example (Y/N): ")
END

PRINT("%n%n*** Critical Gap Example Complete...%n%n Thanks!!!%n%n")

END