Chapter 13 - Traffic Forecasting and Analysis Concepts

13.3. Arterial Traffic Analysis and Design

13.3.2. Traffic Analysis Procedures

The traffic analysis and design generally includes the following elements: the typical section, access management, and intersection design.  The following sections will address each of these areas.

Determination of Typical Section

To begin the conceptual design of an arterial, the number of travel lanes that are needed on the mid-block segments can be estimated based on ideal capacities. The ideal capacity of a two lane roadway is 1,700 vehicles per hour (vph) in each direction. The ideal capacity of a multi-lane roadway is 2,000 vph per lane.

Capacity analysis should be used to check that acceptable levels of service can be achieved with the selected typical section and the design traffic data. The following general guidelines are provided to assist in the process of establishing typical sections:

• Two-lane roadways are generally acceptable only if the DHV are less than 800 vph in either direction.
• Undivided multi-lane roadways are typically limited to areas where the posted speed limit is no greater than 40 mph and the DHV does not exceed 3,000 vph in either direction.
• Continuous two-way left turn lanes may be considered for roadways with typical sections having a number of closely spaced intersections with low-volume streets when the main roadway has no more than four lanes.

Access Management

Access management involves many techniques, ranging from zoning and subdivision regulations to highway design aspects and driveway access controls.  For additional information related to Access Management, see Section 3.5. of this Manual.

For additional information relating to driveway and access controls, including permit procedures, access criteria, and geometric design criteria, refer to the most current version of the GDOT Regulations for Driveway and Encroachment Control.