Interchanges 1

Interchanges

- Flow Channelization

- Interchange Types

• General consideration – Warrants of grade separation and interchanges

1. Design Designation2. Reduction of bottlenecks and recurrent spot congestion3. Safety Improvement4. Site topography5. Road user benefits6. Traffic Volume warrant

• Interchanges - Flow Channelization

BUILDING

FACTORY

EXISTING

NEW ROAD

• Interchanges - Flow Channelization

BUILDING

FACTORY

EXISTING

NEW ROAD

BUILDING

CITY B

CITY A

FACTORY

EXISTING

CITY B

CITY A

FACTORY

EXISTING

BUILDING

Try a T-Intersection

FACTORY

EXISTING

NEW ROAD

FACTORY

EXISTING

BUILDING

NEW ROAD

Try a four-leg providing U-turn

Types of Interchanges

T or Y type interchanges

- With single structures

Discussion 1: Cons & Pros of each design

T or Y type interchanges

- With multiple structures

Diamond Interchanges

- Conventional

Diamond Interchanges

- Variation

Discussion 2:

Conventional vs. varied Diamond interchanges

Identify one design you may find in Lubbock

Single-Point Urban Interchanges (SPUI)

Pros: Well organized left-turnReduced delay compared to DiamondFlatter left-turn radiusHigher capacity

Cons:High costNeed detailed consideration of geometrics and operationHard to handle Skew angle

Under restricted ROW condition

Reconstruction – An example

existingSource: http://www.wsdot.wa.gov/Projects/SR167Extension/designviz/i5interchange_design.htm

proposed

Source: http://www.wsdot.wa.gov/Projects/SR167Extension/designviz/i5interchange_design.htm