Description about the categories of intersection and various aspects while designing a intersection for public use and enhancement in current transportation system

1. CONTINUOUS FLOW
INTERSECTION
By
Pankaj Kumar 120040112
Jiten Dayama 120040109

2. Outline
• Introduction
• Intersection
• Autocad Drawing
• Design details for left-hand side driving
• Traffic operations for left-hand side driving
• Vissim Simulation

3. Introduction
An intersection is the junction at grade of two or more roads either meeting or crossing. It can be at same level
or different level.
Types of Intersections:
• On basis of Road segments
3-way intersection, 4-way intersections,
5-way intersections, 6-way intersections
• On basis of Traffic Control:
Uncontrolled, Yield-controlled, Stop-controlled,
Signal-controlled
• On basis of Lane Design:
Traffic circle, box junction, Roundabout
Eg. Of 4-way intersection/box junction/
Signal-controlled

4. Problems
• Loss of time
• Loss of fuel
• Problems with traffic analysis
• Accidents at traffic lights
• Loss of capacity
Traditional Solution:
• Lane additions at grade
• Grade separated interchanges
Disadvantages:
• At Grade – Lane Additions:
• Large footprint, Needs extensive Right of Way, Expensive, and disruptive
• Grade Separated – Interchanges:
• Large footprint, Needs extensive Right of Way, Eliminates access
Vyttila Junction, one of the busiest junctions in Kochi

5. Intersection
Continuous Flow Intersection (CFI) is a new alternative and innovative
design for an at-grade road junction where vehicles cross before they
enter the intersection. This is done while attempting to turn across the
opposing direction of traffic.
Advantages:
-Improved capacity & Reduced delay and travel time
-Prevent need to add lanes,-Lower cost than other
alternatives
Disadvantages:
-Strict access control, -Often requires extra space,
-Initial driver confusion

6. Usage
• Haddon Township, Audubon and Audubon Park, New Jersey, New
Jersey Route 168 at Nicholson Road, is a hybrid one-leg continuous
flow intersection
• Miami Township, Montgomery County, Ohio, a two-leg CFI
constructed in the spring of 2009, at the intersection of SR 741 and
Miamisburg-Springboro Road/Austin Pike.
Left-turn crossover movement at a partial DLT
intersection in Baton Rouge, LA.

7. Autocad Drawing

10. Vyttila Junction
This junction shows huge traffic as its connects one the major highways in
india. It is located in Kerala in the city of Kochi. It is one of the largest as well as
the busiest intersections in Kerala. CFI can be used here as major traffic which
is caused there only due poor traffic flow maintaining by signals which is the
best quality in CFI that it regulates traffic by providing crossover. Also it has
simple to design hence it can be implemented easily. Distance between nearby
intersection is 2.2 km. Hence it satisfy the minimum condition of distance. Only
negative point is that it lies near urban area, hence that’s a challenge here. Fig.
below show the intersection.

11. Design Details
Junction connects National Highway with other arterial roads
Assumptions: Minimum design speed considered as 80 kmph.
Major road is NH-47 (Trichur) with minor road as Sahodaran Ayyapan Road
T= (V1+ V2)/2*a + D1/V1 + D2/V2
T= total potential CFI right turn split time (sec)
V1= speed (ft/sec) in displaced right turn lane
V2= speed (ft/sec) of opposing through vehicles
a = acceleration (ft/sec²), usually around 7 ft/sec²
D1= distance (ft) for crossover right turn movement measured from crossover right turn stop bar to displaced right turn lane
stop bar at main intersection
D2= distance (ft) for opposing through movement measured from main intersection stop bar to stop bar at crossover right
turn location

12. Design For Roads
Design speed for main road 80 Km/hr (table 1 IRC-86-1983)
Carriageway width: 7.5 m (table 5 IRC-86-1983)
Design speed for secondary road 60 Km/hr (table 1 IRC-86-1983)
Carriageway width: 7m (table 5 IRC-86-1983)
Stopping sight distance(v=80 km/hr)=120m
Stopping sight distance(v=60 Km/hr)=80 m
Alignment-
Super-elevation 4 %
Max friction value 0.15
Min radius of horizontal curve(R ruling):265m (table 10 IRC-86-1983)
Let assume radius of curvature 300 m
• Max f value(assuming e=4 %)=0.128 <0.15
• Length of transition curve(R=300m V=80 Km/hr) = 75 m (table 11 IRC-86-1983)
• No extra width should be provided (table 12 IRC-86-1983: R>300m)
• Vertical minimum gradient 0.2% (for drainage purpose)

13. Final Assumed Design
• Minimum distance between intersection should be greater than 400m.
• Distance between flare to gore is 50m.
• Width of two lanes is 23ft (7m), one lane is 3.8m & 3 lane is 35 ft.
• Radius between flair to gore is 95m.
• Radius range at stop line is 450m- 1200m.
• Crossover radius is 60m to 120m.
• Radius of Back curb is 1m.
• Width of cross over lane is 3.8m.
• Minimum inside radius is 46m.
• Crossover distance 145-175m.
• T= 30 sec

14. Traffic Operation
While the left/right traffic flows through the main intersection, the right-turn traffic
crosses to the right of the oncoming traffic a few hundred feet away. When the
north/south through traffic is allowed through the main intersection, the
north/south right-turn lanes are also allowed through the intersections. All traffic
flow is controlled by traffic signals as at a regular intersection. Right-turn lane and
the straight-through lanes are usually separated by a concrete barrier to reduce
confusion.

15. Vissim Simulation