Alternative Continuous Flow Interchange,...

© 2014 Cal Poly Pomona, Civil Engineering, Railroad Canyon Road Senior Project

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Intersection Control Evaluation Report

This report conforms to the Caltrans Traffic Operations Policy Directive 13-02.

Intersection Control Evaluation (ICE) is a directive issued by the California Department of

Transportation (Caltrans) for all proposed highway intersection projects, whether new or for

improvement. ICE is performed during the early stages of a project, allocating time to study

which types of intersection control alternatives would work. Control types listed by ICE include

stop, signal, roundabout and lane configuration changes. Each is to get ample time for

consideration.

Project Railroad Canyon Road Interchange Improvement

Alternative Continuous Flow Interchange, CFI

Client Cal Poly Pomona

Location An interchange at Interstate 15 with Railroad Canyon Road in the

City of Lake Elsinore, California. Coordinates: 33° 39’ 44.53” N,

117° 17’ 55.17” W

Number of Intersections 3

Current Control(s) Signalized

Need for Control

The project site is located in a heavily traveled corridor within the city of Lake Elsinore. The

interchange exit with Railroad Canyon Road serves as the main arterial between the residences

of the city and major commuting routes along Interstate 15. There are significant truck routes

that pass the area as well. Therefore, it is necessary to assess the feasibility of various control

types for this project.


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Figure 1 – Overview image of the intersections under consideration, numbered 1-3. The CFI

alternative replaces the two circled ramp intersections.


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Figure 2 – Intersection 1, Diamond Drive and Lakeshore Drive/Mission Trail

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Figure 3 – Intersection 2, Diamond Drive and Auto Center Drive/Casino Drive



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Figure 4 – Intersection 3, Railroad Canyon Road and Grape Street/Summerhill Drive



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Alternative Description

A Continuous Flow Interchange (CFI) will replace the existing ramp intersections. A CFI is

where conflicting left turn traffic is channelized away from conflicting through movements in the

intersection. Much of the lane conversion applies to the outer edges where the left turns are free

to enter the ramps instead of waiting a cycle at a standard intersection. There is enough right-of

way to accommodate the lane configuration changes. Traffic analysis show that, with the help of

a signal control, the level of service is better improved than that of the no build condition.

Geometrically, the interchange can be well accommodated for regular and large truck traffic if

including retaining walls at the bridge. Costs for such an alternative may be minimal since there

are no major changes to the roads.

Figure 5 – Image of a CFI in with levels of service for projected 2040 PM volumes.

Figure 6 – A CFI modeled in AutoCAD.




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Step 1 – Configuration Assessment/Screening

Control Alternative Overview Table:

Stop

Control

Roundabout

Control

Signalized

Control

Intersection 1 Diamond Drive

and Lakeshore Drive/Mission Trail

No Yes Yes

Intersection 2

Diamond Drive

and Auto Center Drive/Casino

Drive

No Yes Yes

Intersection 3

Railroad Canyon Road

and Grape Street/Summerhill Drive

No Yes Yes

Intersection 1 – Diamond Drive and Lakeshore Drive/Mission Trail

Stop Control A stop controlled intersection involves placing stop signs at the intersection, making vehicles that

pass through it have to stop and pass with caution. Based on the existing control at the

intersection there is no possibility a stop controlled intersection can handle the volume and

complexity of traffic going through. This alternative will not be considered in engineering

analysis.

Roundabout Control Yield control involves slowing vehicle speed to a safe level while making them pay attention to

other vehicles in the intersection. One type yield control is the roundabout, a typically circular

road where vehicles can enter and exit from different roads. A roundabout can be implemented at

this intersection. There is enough right of way to design a traditional roundabout, possibly with

an increase of interior lanes and a road diet of the surrounding area. This alternative will be

considered further in engineering analysis.

Signalized Control

A signalized control uses traffic lights to coordinate movements in an intersection. The

current control is of this type. A change in timing and/or coordination with other signals is

likely needed. This alternative will be considered further in engineering analysis.


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Intersection 2 – Diamond Drive and Auto Center Drive/Casino Drive

Stop Control A stop controlled intersection involves placing stop signs at the intersection, making vehicles that

pass through it have to stop and pass with caution. Based on the existing control at the

intersection there is no possibility a stop controlled intersection can handle the volume and

complexity of traffic going through. This alternative will not be considered in engineering

analysis.




this intersection. There is enough-right of way to design a traditional roundabout, possibly with



Signalized Control A signalized control uses traffic lights to coordinate movements in an intersection. The current

control is of this type. A change in timing and/or coordination with other signals is likely needed.

This alternative will be considered further in engineering analysis.

Intersection 3 – Railroad Canyon Road and Grape Street/Summerhill Drive

Stop Control

A stop controlled intersection involves placing stop signs at the intersection, making vehicles that

pass through it have to stop and pass with caution. Based on the existing control being signalized,

there is no possibility a stop controlled interchange can handle the volume and complexity of

traffic going through. This alternative will not be considered in engineering analysis.




this intersection. There is enough right of way to design a traditional roundabout, possibly with



Signalized Control A signalized control uses traffic lights to coordinate movements in an intersection. The current

control is of this type. A change in timing and/or coordination with other signals is likely needed.

This alternative will be considered further in engineering analysis.


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Step 2 – Engineering Analysis

Intersection 1 – Diamond Drive and Lakeshore Drive/Mission Trail

Roundabout Control A traffic simulation was run using a traditional roundabout using yield control for entry points.

Lanes from all streets were reduced to two before entering the two lane roundabout. Existing and

predicted 2040 peak hour traffic volume was used. Results from this analysis concluded that the

roundabout will breakdown. Therefore, this alternative will not be considered.

Figure 7 – A roundabout simulation using projected 2040 volumes.



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Signalized A traffic simulation was run using a signalized control. Signals were re-implemented at this

intersection, but with a change of lane configurations of the surrounding streets and a change in

phasing/timing of the signal. Existing and predicted 2040 peak hour traffic volume was used.

Results from this analysis concluded that signalized control can handle the input. The Level of

Service at this intersection, along with other employed alternatives, during peak hours reaches a

D. This is an improvement from the existing conditions at a LOS of F.

Figure 8 – The existing signalized intersection with projected 2040 PM traffic volumes.

Other Considerations Other intersection control methods, including left turn offsets, are likely to fail do to the need for

drastic lane configuration changes and purchase of considerable right of way.

It is recommended that the alternative selections be put into the study area network of

intersections to gauge its effect. However, since the standalone analysis already fails, then

inclusion into the network is not necessary.



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Intersection 2 – Diamond Drive and Auto Center Drive/Casino Drive

Roundabout Control A traffic simulation was run using a traditional roundabout using yield control for entry points.




Figure 9 – A roundabout using projected 2040 volumes.











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Intersection 3 – Railroad Canyon Road and Grape Street/Summerhill Drive

Roundabout Control. A traffic simulation was run using a traditional roundabout using yield control for entry points.




Figure 11 – A roundabout using projected 2040 volumes.



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Evaluation Summary

Stop control, roundabout control and non-traditional control at intersections 1, 2 and 3 are not likely

to work due to high volumes that are projected to exist within the life of the proposed project, year

2040. Therefore these alternatives will be rejected.

Based on an evaluation using predicted traffic conditions, signalized control for all intersections is

the likely candidate to be chosen for the CFI and therefore recommended for the project.

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