A truck-restricted road, as determined by the controlling governmental authority, prohibits trucks larger than a certain size and weight. A truck-discouraged road is one that is open for local deliveries, but unsuitable for through trucks, as determined either by the controlling authority or by PC*MILER.
These roads can be seen on the map by setting the Map tab > Map Features dialog with the Truck Restrictions checkbox.
In accordance with these regulations, PC*MILER does not use truck-restricted roads when routing vehicles larger or heavier than the restricted size or weight. PC*MILER avoids routing over truck-discouraged roads whenever possible, with the following exceptions: if the destination is located on such a road; if avoiding the truck-discouraged road will add a very significant amount of time and distance to a route; or if you have marked the road to be favored.
However, you can override these restrictions using the features described below. (This assumes that you have been granted permission to use these roads from the controlling authority, or that you are going to be using special equipment.)
Overriding Restricted Roads
To set PC*MILER to override truck restrictions by default, click the Routes tab > Profiles and edit the Default route profile (or whichever profile you use regularly). In the Routing Preferences tab, set Restrictions to Override, then save your edit. Override relaxes specialized road restrictions—such as those based on weight, time of day or "delivery only"—but PC*MILER will still avoid roads that are prohibited or discouraged for truck travel.
Overriding Discouraged Roads
For a road that is flagged as “truck-discouraged” (versus “truck-restricted”), in addition to overriding the road, you must designate all the road segments on it as favored to make it fully truck-accessible.
IMPORTANT: Your Route Modifiers (avoid/favor preferences) will affect routing only when Routing Preferences > Custom Roads > Use Route Modifiers is selected in the Route Options dialog or current route profile. This option is turned off by default.