1. Highway Functional Classification Chapter 16 Dr. TALEB M. AL-ROUSAN

2. Highway Functional Classification  Highways are classified according to their respective functions in terms of the character of the service they are providing.  Primary Classification: Highways and streets are described as rural or urban roads.  Urban and rural areas have different characteristics (type of land and population density) which significantly influence travel patterns.  Second Level Classification for Urban and rural roads: Principal arterials (includes freeways) Minor arterials Major collectors Minor collectors Local roads and streets.

3. Functional System of Urban Roads  Urban roads: all highway facilities within urban areas.  Urban areas: designated by state and local officials, have population of (5000) or more.  Urban areas divided into: Urbanized areas (population > 50,000) Small urban areas (population 5000 – 50,000)  Urban roads are functionally classified into: principal arterials, minor arterials, collectors, and locals.  See Figure 16.1 for functional classes of suburban roads.

5. Urban Principal Arterial System  Serves the major activity center of the urban area.  Consists of the highest-traffic volume corridors.  Carries most trips with origin or destination within urban area.  Serves trips by passing the CBD.  All controlled-access facilities are within this system.  Further divisions (subclasses) based on the type of access to the facility: 1. Interstate, with fully controlled access and grade separation interchanges. 2.Expressways, have controlled access but may include at-grade intersections. 3.Other principal arterials, with partial or no controlled access.

6. Urban Minor Arterial System  Streets and highways that interconnect with the urban primary arterials.  Serves trips of moderate length.  Places more emphasis on land access than primary arterial.  Might serve local bus routes and connect communities but do not go through neighborhoods.  Spacing is usually not less than 1 mile.

7. Urban Collector & Local Street System  Collector main purpose: collect traffic from local streets in the residential areas or in CBDs and convey it to the arterial system.  Local streets: all other streets within the urban area that are not included in the other three systems.  Local streets main purpose: to provide access to adjacent land and to the collector streets.  Through traffic is deliberately discouraged on local streets.

8. Functional System of Rural Roads  Rural roads are the highway facilities outside urban areas.  Rural roads are categorized as: principal arterials, minor arterials, major collectors, minor collectors, and locals.  See Figure 16.2 for functional classes of rural roads.

10. Rural Principal Arterial System  Consists of network of highways that serve most of interstate trips and part of intrastate trips.  Most of highway trips between urbanized areas and small urban areas are made on this system.  Subclasses: Freeways: divided highways with full controlled access and no at-grade intersections. Other principal arterials: all principal arterials not classified as freeways.

11. Rural Minor Arterial System  Augments the arterial system in the formation of a network of roads that connect cities, large towns, and other traffic generators (resorts).  Travel speeds are high as on the principal arterial system.

12. Rural Collector System  Carry traffic within individual counties  Trip distances are shorter than those on arterials. Major collectors: carry traffic to and from county seats and large cities that not directly served by the arterial system. Minor collectors: collect traffic from local roads and convey it to other facilities.

13. Rural Local Road System  All roads within the rural area not classified with the other systems.  Serves trips of relatively short distances  Connects adjacent lands with the collector roads.

14. Other Types of Roads  According to jurisdictional responsibilities (public works, municipalities).  Freeways  Main roads  Secondary roads  Collector roads  Local roads  Belt or ring roads  Radial roads (passes through city center)

15. Primary Highway Classifications RuralUrban Land CheaperLand Expensive Speed more important than access Access more important than speed Pedestrian facilities less needed, shoulders are more needed Pedestrian facilities needed (curbs, side walks, crossings) Street lighting less or not neededStreet lighting needed Loading & unloading Trucks allowedTrucks are not usually allowed LOS is higherLOS is low due to slow speed and high volumes Less accidentsMore accidents No cyclingcycling

16. Types of Lanes  Climbing lanes  Escaping lane  Acceleration lanes  Deceleration lanes  Turning (storage) lanes  Parking (stopping) lanes  Bus lanes  Bicyclist lanes  Overtaking lanes