Cross-Section

• GEOMETRIC DESIGNS - Deals with dimensioning of the elements of highways, such as vertical and horizontal curves, cross sections, etc.
• A Cross Section is a vertical cut through the road or railway, taken perpendicular to the centerline.
• The right-of-way is the total area acquired for the road or railway, including the lanes or tracks and areas for shoulders, slopes, and utilities. It defines how much space is needed to complete the road or railway construction and maintenance, including future expansions.
• The right-of-way width:

  • Two-lane Urban Collector Street = 40-60 ft
  • Two-lane Arterial = Desirable minimum 84 ft
  • Undivided Four-lane Arterial = 64-108 ft
  • Divided Arterial = Approximately 120-300 ft
  • Freeway= Minimum depends on lanes and frontage road
• The width of the ROW depends on the type of road or railway:

  • Two-lane Urban Collector Street = 40-60 ft
  • Two-lane Arterial = Desirable minimum 84 ft
  • Undivided Four-lane Arterial = 64-108 ft
  • Divided Arterial = Approximately 120-300 ft
  • Freeway= Minimum depends on lanes and frontage road
• The carriageway is the portion of the roadway used by vehicles for driving, including the lanes where cars, trucks, and other vehicles travel.
• TYPES OF CARRIAGEWAY: Single Carriageway

  Road with one or more lanes without a physical barrier separating opposing traffic.

  Ex: Local roads, rural highways.
• TYPES OF CARRIAGEWAY: Dual Carriageway

  Road with two separate carriageways, divided by a median or barrier.

  Ex: Freeways, expressways, major highways.
• TYPES OF CARRIAGEWAY: Multilane Carriageway

  Road with multiple lanes in each direction to handle higher traffic volumes and allow overtaking. Ex: Major urban roads, interstates.

  Ex: Major urban roads, interstates.
• A travel lane is the section of a roadway specifically designated for vehicle movement, excluding shoulders and bicycle path. Typically, a roadway will have two or more travel lanes to accommodate traffic.
• Lane width affects traffic flow, safety, and capacity. Standard lane widths range from 9 to 12 feet, depending on the type of road and traffic volume.
• Shoulders are the areas adjacent to the travel lanes on a roadway. They serve as a safety buffer and provide structural support to the pavement. In railroad engineering, similar areas exist alongside the tracks for maintenance and safety purposes.
• PAVED SHOULDERS Constructed from asphalt or concrete, matching the main pavement material.
• UNPAVED SHOULDERS Made of gravel, crushed stone, or soil. Often stabilized with additives like lime or cement to enhance durability.
• Medians are structures or spaces that separate opposing lanes of traffic on divided highways.
• TYPES OF MEDIAN: RAISED MEDIAN

  Constructed from materials like concrete, asphalt, or landscaped with

  grass, shrubs, or trees. Common in urban areas for enhanced safety and aesthetics.
• TYPES OF MEDIAN: Depressed Medians:

  Lowered sections that provide additional space for vehicle recovery and improve drainage. Common on high-speed highways.
• Barriers - typically placed along road edges or medians on highways. Made of materials like concrete or steel to prevent vehicles from crossing into oncoming traffic or veering off the road. Designed to absorb and redirect impact forces, minimizing damage during collisions.
• Guardrails - placed along the roadside, especially near steep slopes, curves, or hazardous areas. Used to guide vehicles back onto the road and protect against drop-offs or obstacles.
• Cross slopes - are essential for ensuring proper drainage of water from the road surface. High-type pavements typically have it of 1.5% to 2%. It prevents water from pooling on the surface, reducing the risk of hydroplaning and skidding.
• Curbs are raised structures made of either Portland cement concrete or bituminous concrete (rolled asphalt) that are used mainly on urban highways to delineate pavement edges and pedestrian walkways. It is

  also used to control drainage, improve aesthetics, and reduce the right of way.
• Gutters or drainage ditches are usually located on the pavement side of a curb to provide the principal drainage facility for the highway. They are sloped to prevent any hazard to traffic, and they usually have cross slopes of 5 to 8 percent and are 1 to 6 feet wide.
• Sidewalks are required in areas with high pedestrian concentrations, such as adjacent to schools, industrial plants, and local businesses.
• BALLAST a crushed stone or gravel material that is used to support and level the tracks in a railroad track bed.
• SLEEPER (TIES) are laid between two rail tracks to maintain the gauge. Sleepers are laid on the ballast and these uniformly distribute the wheel loads to the ballast.
• RAILS - are steel girders providing a continuous, level surface for trains.
• FASTENING SYSTEMS collection of components and mechanisms used to secure and maintain the position and alignment of the railway track
• CANTS the angle at which the outer rail is elevated compared to the inner rail on a curved section of track.
• SUPERELEVATION the amount by which the outer rail of a railway track is raised above the inner rail on a curved section of the track.
• Ditches are excavated channels or trenches designed to manage water drainage around railway tracks.
• DRAINAGE SYSTEMS managing water around railway tracks and infrastructure.