7. والتكنولوجيا للهندسة العالي مصر معهد–المدنية الهندسة قسم-المنصورة
Travel Lanes
• In general, the number of travel lanes should be based on
the design traffic volume and level of service.
• No. of travels lanes in both directions are usually equal.
• Travel lanes generally range in width from 10 to 13 ft.
(3 to 3.95 m).
• Typically is 12 ft (3.65 m)
• Under extreme circumstances, a width of 9 ft (2.75 m) may
be used.
8. والتكنولوجيا للهندسة العالي مصر معهد–المدنية الهندسة قسم-المنصورة
Shoulder
• Shoulders usually range in width from 2 ft (0.6 m) for minor
local roads. (6 to 8 ft – 1.8 to 2.44 m- is preferred) to 12 ft
(3.65 m) for major highways.
• Typical cross slope is 3% for paved shoulders and 5% for
unpaved shoulders .
9. والتكنولوجيا للهندسة العالي مصر معهد–المدنية الهندسة قسم-المنصورة
Medians
• A median is a wide strip of a highway used to separate
traffic traveling in opposite directions.
• Offer a recovery area for errant vehicles
• Provide an area for emergency stopping
• Serve as a safe waiting area for left-turning and U-turning
vehicles
• Decrease the amount of headlight glare
• Allow for expansion to future lanes
• Medians can be Flushed – Depressed- Raised.
12. والتكنولوجيا للهندسة العالي مصر معهد–المدنية الهندسة قسم-المنصورة
Cross (Side) Slope
• The slope selected generally depends on the type of
pavement used.
• Typical cross slope of 1.5 to 3% is recommended.
• Cross slopes greater than 2% should be avoided (for
safety).
13. والتكنولوجيا للهندسة العالي مصر معهد–المدنية الهندسة قسم-المنصورة
A curb is a raised element that is used, among other things,
to denote the edge of a roadway.
Functions of curbs
• Drainage control
• Roadway edge delineation
• Enhanced appearance
• Right-of-way reduction
• Delineation of pedestrian walkways
• Reduction of maintenance operation
Types of curbs:
Vertical curbs -- discourage vehicles from leaving the roadway,
not desirable on high-speed highways, desirable on urban
roads, and along long walls, tunnels to protect safety walks.
Sloping curbs -- vehicle can cross them readily when required,
used at median edges, to outline channelizing islands, at the
outer edge of the shoulder.
Curbs
14. والتكنولوجيا للهندسة العالي مصر معهد–المدنية الهندسة قسم-المنصورة
Curbs
• Barrier Curbs
• The purpose of a barrier curb is to prevent or limit the possibility of
a vehicle’s leaving the roadway.
• A general rule of thumb is that barrier curbs should not be used
when the design speed is greater than 40 mph.
• Mountable Curbs
• A mountable curb offers the advantage that a vehicle can cross it
when necessary.
17. والتكنولوجيا للهندسة العالي مصر معهد–المدنية الهندسة قسم-المنصورة
Sidewalks
• Sidewalks are an integral part of city roads, sometimes
provided in rural areas.
• In residential areas the sidewalk width varies between
1.2 to 2.4 m.