2. 2
Static Characteristics
• Size:
• Design of lane widths, parking bays, etc…
• Vertical clearance
• Weight:
• Pavement design, bridge design, axle loads
• Maximum grade
• Radius of Curvature:
• Intersection design
• Interchange ramps
3. 3
Kinematic (Dynamic) Characteristics
• Acceleration (Constant or variable):
• Passing maneuvers
• Gap acceptance
• Dimensions of freeway ramps and passing lanes
• Motion elements (Distance and Velocity)
4. 4
Functional classification of highways
• Highways are classified either by
– The function they serve (functional classification)
– The entity responsible for their construction and
maintenance (jurisdictional classification)
• Two concepts are used when classifying highway by
their function
– Mobility: continuous travel
– Accessibility: direct access to abutting (next to or adjacent)
property
• Some roads serve one of these two function while
few can satisfy both
8. 8
Three Major Roadway Classes and their
functions:
• Arterial (high mobility, low access, long trips,
fast speeds)
• Collector (moderate, moderate, moderate,
moderate)
• Local (low, high, short, slow)
9. 9
Roadway Functional Classes
• Determined by characteristics:
– Function
– access density
– traffic demands
– trip length
– expected speed
11. 11
Freeway versus expressway
• The distinction between freeways and expressway is
based on the accessibility control
– Freeways have a full control of access [access or exit are
permitted only at controlled locations (exit ramp)]
– Expressways have a partial access control. (access or exit
are maybe permitted directly from or adjacent land or via
a limited number of at grade intersections)
12. 12
Rural road classification
Principal Arterials
• Function: Long disance Travel and Connect
urbanized areas
• Characteristics: Long trips, no stubs, high
speed, widely spaced, full/partial access
control
• Subclasses: Freeways, Other non-Freeways
with access control
13. 13
Minor Arterials
• Function: connect small urban areas with
major trip generators
• Characteristics: Moderate everything
(routes, speed, spacing, mostly mobility)
14. 14
Rural Collectors
• Major Collectors: Connect small twon to large towns not
served by arterials, link entities with nearby arterials, urban
areas
• Minor Collectors: Serve remaining small towns, link local
traffic generators with rural areas
• Characteristics: Shorter, Moderate Speeds (in rural areas),
Intermediate spacing
15. 15
Rural Local Roads
• Function: Provide access to land on collector
network, serve short distance travel
• Characteristics: Short routes that terminate at higher
classes, relatively low speeds, intermediate spacing
16. 16
Urban Functional System
Principal Arterials
• Functions: carry most trips entering/leaving urban
area, serve intra-urban trips, carry intra-urban and
intercity bus routes, provide continuity to rural
arterials
• Characteristics: longest distance routes and
highest volume, high speed, spacing is less than 1
km in CBD and greater than 8 km in urban fringe,
full/partial access control
• Subclasses: interstates, other freeways and
expressways, other principal arterials with partial
access control
17. 17
Urban Minor Arterials
• Functions: interconnect with and augment
principle arterials, accommodate moderate
length trips, distribute traffic, carry local buses,
provide intra-community continuity, connect to
urban collectors
• Characteristics: moderate trip length high
volumes, moderate speeds, spacing 0.2 to1.0 km
in CBD and 3 to 5 km in suburbs
18. 18
Urban Collectors
• Functions: Provide traffic circulation within
residential neighborhoods and industrial/commercial
areas, Collect traffic from locals and channel to
arterials, Carry local buses, Provide some direct land
access
• Characteristics: Shorter than minor arterials,
Moderate speeds, Spacing intermediate to arterials,
Penetrates residential neighborhoods
• Subclasses: major and minor
19. 19
Urban Locals
• Functions: Provide direct access to land,
Connect properties to higher class streets (i.e.,
collectors)
• Characteristics: Short in length, Dead end –
terminate at collections, Low speeds, No bus
routes
22. 22
Cross section components
• Highways are categorized into
– Divided highways
– Undivided highways
• The distinction is based on the viability of median (Divided highways).
• The components of divided highways within the right of way are
– Carriageway or travelling lanes
– Median
– Shoulder
– Ditches
– Side-slopes
– Barrier
– Marking
– Cross section slope
