8.1.1 Introduction
Freeways are arterial highways with full control of access. They are intended to provide high levels of safety and efficiency in the movement of large volumes of traffic at high speeds.
Freeways may be provided in both rural and urban areas. All freeways in rural areas are designed for the rural context; the rural town context is generally not applicable to freeways.
Freeways in urban areas may be provided to fit all contexts including suburban, urban, and urban core.
Design criteria presented in this chapter is applicable to new construction of freeways, reconstruction of existing freeways and the conversion from a non-access controlled arterial to a freeway.
This chapter discusses the features and design criteria for freeways and includes the following sections and subsections:
8.1 Design Considerations
- 8.1.1 Introduction;
- 8.1.2 Target Design Values;
- 8.1.3 Design Speed;
- 8.1.4 Design Traffic Volumes;
- 8.1.5 Level of Service;
- 8.1.6 Travel Lane Width and Number of Lanes;
- 8.1.7 Shoulders;
- 8.1.8 Speed Change Lanes;
- 8.1.9 Medians;
- 8.1.10 Curbs;
- 8.1.11 Cross Slope and Superelevation;
- 8.1.12 Grades;
- 8.1.13 Roadside Design;
- 8.1.14 Structures;
- 8.1.15 Vertical Clearance;
- 8.1.16 Ramps and Terminals;
- 8.1.17 Outer Separations and Borders;
- 8.1.18 Frontage Roads;
- 8.1.19 Collector-Distributor Roads;
- 8.1.20 Crossing Facilities;
- 8.1.21 Access Control;
- 8.1.22 Managed Lanes and Toll Facilities; and
- 8.1.23 Tunnels.
8.2 Rural Design Elements
- 8.2.1 General Design Considerations
8.3 Suburban Design Elements
- 8.3.1 General Design Considerations
8.4 Urban Design Elements
- 8.4.1 General Design Considerations;
- 8.4.2 Depressed Freeways;
- 8.4.3 Elevated Freeways;
- 8.4.4 Ground Level Freeways;
- 8.4.5 Combination-Type Freeways; and
- 8.4.6 Special Freeway Designs.
8.5 Urban Core Design Elements
- 8.5.1 General Design Considerations
This chapter is organized with an introductory section on the general design considerations for freeways, followed by separate design discussions for freeways in urban, urban core, suburban, and rural contexts.