Snow Blockage and Flooding. The effects of snow are not usually considered
an obstruction to traffic flow. In those cases where snow blockage is regular or recurrent
and serious, the route classification formula will be followed by a T. The effects of flooding
on traffic flow are not usually considered in route classification either. Where flooding is
regular or recurrent and serious, the route classification formula will be followed by a W. In
the case where the conditions for snow blockage and flooding both exist as described above,
both a T and a W will follow the route classification formula.
Examples. Two examples of route classification formulas follow:
20/Z/40/∞. This example describes a fair-weather route (Z), with a minimum
traveled way of 20 meters, and a MLC of 40. Overhead clearance is unlimited
(∞), and there are no obstructions to traffic flow. This route, based on its
minimum width of traveled-way, accommodates both wheeled and tracked,
single-flow traffic without obstruction.
20/Z/40/∞ (OB). This example describes a route with characteristics similar to
those of the previous example, but with an obstruction. This obstruction could
consist of overhead clearances of less than 4.3 meters, grades of 7 percent or
greater, curves with a radius of 25 meters and less, or a ford or a ferry.
Twenty feet of traveled way limits this route to single-flow traffic without a
width obstruction. If the route is to be used for double-flow traffic, 20 meters
of traveled way constitutes an obstruction and is indicated in the formula as
Electronic Transmission of Route Information. Reconnaissance personnel must often
provide commanders with immediate information on selected routes. This is usually
accomplished by reporting the route as open or closed. Suggested formats for both
situations have been developed (Figures 2-3 and 2-4, page 2-6). Although designed for
electrical transmission, the formats can be used to supplement overlays or map
Summary. Remember the following when calculating a route classification formula:
The numbers and letters used to express route width, route type,
MLC, overhead clearance, obstructions to traffic, and special
conditions are recorded in a standard sequence.
The recorded traveled-way width is the minimum width measured on
An X, Y, or Z will identify the type of route.
The MLC is usually the lowest class of bridge on the route, regardless
of traffic type or flow. If no bridge is present on the route, the worst
section of the route will govern the MLC.
If no overhead obstruction exists, must be recorded in the formula.
If obstructions exist on the route, an OB will be noted in the formula.