ADT-- Average daily traffic that results from dividing a traffic count obtained during a given time period by the number of days in that time period.

Cadastral Survey-- A survey that identifies the legal boundaries between public and private lands.

Design Speed-- The maximum safe speed that can be maintained when conditions permit the design features of the highway to govern.

D-- Directional distribution. The percentage of the two-way traffic volume traveling in the direction of interest, expressed as a decimal.

DHV-- Design hour volume. The two-way traffic volume that is determined by multiplying the ADT by a percentage factor called the K-factor (see below).

DDHV-- Directional design hour volume expressed as vehicles per hour.

Functional Class-- The classification of roadways by operational status such as freeway, arterial, collectors and local.

K-factor-- The proportion of daily traffic occurring during the peak hour, expressed as a decimal. For design purposes, K represents the proportion of AADT occurring during the thirtieth highest peak hour of the year.

Located Centerline Survey-- A survey of the centerline of a planned or existing highway.

Planimetric Map-- Illustrates features such as roads, buildings, water, fences, vegetation, bridges, railroads.

Stations-- Points along a line (usually a survey line) of equal distance designated either in feet or meters. Points at multiples of 100 meters or feet are typically called full stations.

Topographic Map-- Illustrates elevation with the use of contour lines and spot elevations.