This document discusses elements of highway cross sections, including the roadway, median, and roadside. It describes key components of the roadway like travel lanes and shoulders. Travel lanes are meant to guide drivers and support vehicles, and their width depends on factors like traffic volume and environment. Shoulders provide lateral support and space for avoidance or emergency stopping. The document also outlines different types of medians and their functions in separating opposing traffic and providing drainage or space for future lanes. It notes design considerations for elements like cross slope and barriers.

1. Dr. Lina Shbeeb
Cross section
Transportation Engineering

2. Dr. Lina Shbeeb
Cross Section Elements
1. Roadway
2. Median
3. Roadside
Roadway Components
1. Travel Lanes
2. Shoulders
Source:http://www.fhwa.dot.gov/environment/flex/ch06.htm

3. Dr. Lina Shbeeb
Two-lane highway cross section

4. Dr. Lina Shbeeb
Travel lane/carriageway
 Function: guidance to drivers
and vehicle support
 Pavement types:
 Paved
 (Flexible pavement)
 Asphalt concrete,
 surface treatment
 Rigid pavement
 Unpaved
 Selection Criteria:
 Traffic volume and composition
 Soil characteristics
 Availability of materials
 Environmental issues including
energy conservation
 Cost analysis (Initial cost,
maintenance cost and operating
cost)

5. Dr. Lina Shbeeb
Travel Lane width
Environment Width
Ideal 3.6 m (12ft)
Urban area with restriction 3.5 m (11ft)
low speed/urban roadways 3.0 m (10ft)
low volume rural and
residential roadways
2.7 m (9 ft)
shared outside lane with bike 4.2 m (14 ft)

6. Dr. Lina Shbeeb
Roadway Component – Shoulders
1.Functions:
a. Lateral Support
b. Avoidance Space
c. Emergency Stop
d. Turning/Passing at
Intersections
e. Pedestrian use in rural area.
2.Geometry
0.6 to 3.6 m width it could be
either paved or Unpaved surface
with slope 2 to 6% (paved), 4 to
6% (unpaved)

7. Dr. Lina Shbeeb
Cross Section Element - Median
1. Functions:
a. Separation from opposing traffic
b. Drainage
c. For future lanes, recovery,
access control
a. Aesthetics
2. Type
a. Depressed (rural arterials, 6:1
preferred? 4:1 min)
b. Raised (urban arterials)
c. Flush (urban/sub. some rural) – can
be painted with double yellows to limit
access.
d. Median barrier
3. Width – varies according to their function,
the availability of space and cost)

8. Dr. Lina Shbeeb
Cross Slope
 Slope perpendicular to flow of traffic on
tangent section
 Rural – normal crown – uniform slope from
center to edge of pavement (cross slope
break typically at centerline)
 Urban – parabolic shape sometimes (gutter
capacity)
 Rate of Cross Slope (1.5% to 6%, high
value for low volume roads)

9. Dr. Lina Shbeeb
Other elements of highways
•Roadside Barriers
– Separates vehicles from
hazardous conditions
•Curbs and Gutters
– Provides channelization
and drainage
•Guide Rails
– Longitudinal barriers which
prevent vehicles from
leaving roadbed (Box, W-
beam and wire)
Roadside barrier
Median barrier