"The geometric design of roads is the branch of highway engineering concerned with the positioning of the physical elements of the roadway according to standards and constraints."
Designing the layout, alignment and dimensions of roadways to ensure safe and efficient travel of vehicles and pedestrians.
Geometric design principles: This topic covers the fundamental concepts that underpin geometric design in traffic operations, including alignment, sight distance, and turning radii.
Roadway elements: This topic focuses on the various components that make up a roadway, including lanes, shoulders, medians, and curves.
Traffic flow theory: Understanding how traffic flows through a roadway network is essential to designing effective geometric solutions to traffic issues.
Intersection design: Intersections are key points in any roadway network, and proper geometric design can help improve the safety and efficiency of traffic flow through these areas.
Roundabouts: Roundabouts are a popular traffic control solution that requires unique geometric design principles.
Horizontal and vertical curves: These design elements are critical for ensuring safe travel through curves and ensuring that drivers are aware of upcoming changes in the road.
Design speed: Understanding the appropriate design speed for a roadway is essential for ensuring that the operating speed of traffic is safe and efficient.
Site distance: This topic covers the range of visibility that is needed for various types of roadway elements, including curves, intersections, and passing zones.
Superelevation: This design element helps ensure that vehicles maintain lateral stability when traveling through curves, thereby reducing the risk of accidents.
Gradients: Gradients, or the slope of the roadway, can affect the speed at which vehicles travel and the ability of drivers to maintain control of their vehicles.
Roadway capacity: This topic covers the amount of traffic that a roadway can safely and efficiently handle, and includes concepts like lane width, shoulder width, and vehicular spacing.
Traffic signals: Effective geometric design of traffic signal systems can ensure that intersections are safe and efficient for all users.
Pedestrian and bicycle facilities: Proper geometric design can help ensure that pedestrian and bicycle facilities are safe, accessible and efficient.
Parking lots and driveways: Geometric design of parking lots and driveways can help ensure that vehicles can safely and efficiently access and exit these areas.
Road safety audits: Road safety audits are a critical step in identifying potential safety hazards along a roadway, and geometric design principles play a central role in this process.
Roundabouts: Circular intersections that require vehicles to travel around a central island.
Interchanges: Grade-separated intersections or junctions that allow vehicles to pass through without stopping or crossing other traffic.
Crosswalks: Designated areas for pedestrians to safely cross streets.
Medians: Physical dividers between opposing lanes of traffic.
Curb extensions: Extensions of the curb into the roadway that narrow the roadway and shorten pedestrian crossing distances.
Speed humps: Raised areas for the purpose of slowing down traffic.
Traffic circles: Circular traffic patterns that require traffic entering to yield to traffic already in the circle.
Lane markings: Painted lines on the road indicating where vehicles should travel.
Bike lanes: Designated lanes for bicyclists to ride in.
Turning lanes: Designated lanes for vehicles to turn onto another roadway or street.
Raised intersections: Intersections where the roadway is elevated to the level of the sidewalks.
Traffic calming chicanes: Series of tight curves requiring drivers to slow down.
Diverging diamond interchange: A type of diamond interchange where vehicles temporarily cross over to the opposite side of the road.
"The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage."
"Geometric design also affects an emerging fifth objective called 'livability,' which is defined as designing roads to foster broader community goals."
"Designing roads to foster broader community goals, including providing access to employment, schools, businesses, and residences."
"Accommodate a range of travel modes such as walking, bicycling, transit, and automobiles."
"Minimizing fuel use, emissions, and environmental damage."
"Geometric roadway design can be broken into three main parts: alignment, profile, and cross-section."
"The alignment is the route of the road, defined as a series of horizontal tangents and curves."
"The profile is the vertical aspect of the road, including crest and sag curves, and the straight grade lines connecting them."
"The cross-section shows the position and number of vehicle and bicycle lanes and sidewalks, along with their cross slope or banking."
"Cross sections also show drainage features, pavement structure, and other items outside the category of geometric design."
"The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage."
"The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage."
"Geometric design also affects an emerging fifth objective called 'livability,' which is defined as designing roads to foster broader community goals."
"The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage."
"Combined, they provide a three-dimensional layout for a roadway."
"Designing roads to foster broader community goals, including providing access to employment, schools, businesses, and residences."
"Accommodate a range of travel modes such as walking, bicycling, transit, and automobiles."
"The alignment is the route of the road, defined as a series of horizontal tangents and curves."
"Cross sections also show drainage features, pavement structure, and other items outside the category of geometric design."