Intelligent Roadway Information System

Slow Traffic Warning

Warning messages for slow traffic can be displayed on DMS using DMS actions. A [slow ] action tag in the message pattern will be replaced with the appropriate value. Additionally, the entire message will be displayed only in the presence of slow traffic. This tag has the following format:

[slow speed,distance,mode ]


  1. speed: Highest speed to activate the warning, in mph.
  2. distance: (tenths of mile) to search for slow traffic, relative to the DMS location.
  3. mode: Tag replacement mode (none if omitted)
    • none: a blank string
    • dist: distance rounded to nearest mile
    • speed: speed rounded to nearest 5 mph


Display message if traffic slower than 35 mph within 1 mile:


Display message if traffic slower than 40 mph within 6 miles:

SLOW TRAFFIC[nl][slow40,60,dist] MILES[nl]USE CAUTION

Display message if traffic slower than 45 mph within 0.5 miles:

[slow45,5,speed] MPH[nl]1/2 MILE[nl]AHEAD