CONTINUOUS FLOW INTERSECTION

CONTINUOUS FLOW INTERSECTION By Pankaj Kumar 120040112 Jiten Dayama 120040109

OutlineIntroductionIntersection Autocad DrawingDesign details for left-hand side drivingTraffic operations for left-hand side drivingVissim Simulation

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

ProblemsLoss of time Loss of fuelProblems with traffic analysisAccidents at traffic lightsLoss of capacity

Traditional Solution: Lane additions at gradeGrade separated interchanges

Disadvantages: At Grade Lane Additions:Large footprint, Needs extensive Right of Way, Expensive, and disruptiveGrade Separated Interchanges:Large footprint, Needs extensive Right of Way, Eliminates access

Vyttila Junction, one of the busiest junctions in Kochi

IntersectionContinuous 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 alternativesDisadvantages:-Strict access control, -Often requires extra space, -Initial driver confusion

Usage

Haddon Township, Audubon and Audubon Park, New Jersey, New Jersey Route 168 at Nicholson Road, is a hybrid one-leg continuous flow intersectionMiami 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.

Autocad Drawing

Vyttila JunctionThis 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 thats a challenge here. Fig. below show the intersection.

Design DetailsJunction connects National Highway with other arterial roadsAssumptions: Minimum design speed considered as 80 kmph.Major road is NH-47 (Trichur) with minor road as Sahodaran Ayyapan RoadT= (V1+ V2)/2*a + D1/V1 + D2/V2T= total potential CFI right turn split time (sec)V1= speed (ft/sec) in displaced right turn laneV2= speed (ft/sec) of opposing through vehiclesa = acceleration (ft/sec), usually around 7 ft/secD1= distance (ft) for crossover right turn movement measured from crossover right turn stop bar to displaced right turn lane stop bar at main intersectionD2= distance (ft) for opposing through movement measured from main intersection stop bar to stop bar at crossover right turn location

Design For Roads

Design speed for main road80 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)=120mStopping sight distance(v=60 Km/hr)=80 m

Alignment-Super-elevation4 %Max friction value0.15Min radius of horizontal curve(R ruling):265m(table 10 IRC-86-1983)Letassume radius of curvature300 mMax f value(assuming e=4 %)=0.128 300m)Vertical minimum gradient0.2% (for drainage purpose)

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

Traffic OperationWhile 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 aconcrete barrier to reduce confusion.

Vissim Simulation