ITE Journal - August 2020 - 44

Unlike other innovative intersections such as Diverging Diamond
Interchange (DDI) and Continuous Flow Intersections (CFI), a
noticeable feature of this design is that it does not impact connectivity and access to properties in the vicinity of the intersection, as
is the case with DDI and CFI. Eliminating direct access or limiting
access to corner properties has shown to negatively impact the
businesses' economic health, especially if they are "in and out"
locations, such as gas stations or convenient stores. Patrons often
prefer easy "in and out" locations, and tend to avoid venues that are
cumbersome and time-consuming to access.
Another potentially negative consequence of eliminating direct
access, as occurs with a DDI, is forcing traffic to go to adjacent
intersections that might already be congested or at near saturation
flow-rate. This could cause them to operate at a failed level of
service due to the additional diverted traffic.
A third and important issue would be losing the operational
flexibility element in the design where the number of phasing
sequences are limited due to geometric layout, and therefore not as
effective to fluctuating traffic pattern or volume. Obviously, major
factors such as right of way and construction costs play a big role
in which approach or design is selected over another. However, all

Roadway Engineer (Tampa, FL)
Provide design support to Project Managers and Project
Engineers during the planning, design and construction
phases of FDOT, County and City transportation
projects. Experience to include working with FDOT
drainage design manuals, Bluebeam, Adobe Acrobat,
AutoCAD and Microstation.
Mail resume referencing job code# 320RE to
BCC Engineering, LLC, ATTN: Human Resources Manager,
6401 SW 87th Avenue, Suite 200, Miami, Florida 33173.

Au gust 2020

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options should be evaluated, not only based on the cost and right
of way (ROW) availability, but also based on operational flexibility,
connectivity, and accessibility factors with short- and long-term effects
to the interchange itself, to adjacent properties and intersections.
Unlike DDI and CFI, the Flipped Left Diamond Interchange
does not eliminate direct connectivity between frontage roads, and
it does not limit access to corner properties. FLDI also provides
operational flexibility that is capable of enhancing capacity at
the interchange, better handling of fluctuation in traffic demand
and patterns, and provides for additional traffic signal phasing
sequences that would be crucial for improved traffic signal synchronization along the arterial. This occurs by allowing utilization of
left-turn lead-lag or conditional service operation where a left turn
can be serviced twice both as a leading and lagging phase.
In order to make this project a success, staff from the Texas
Department of Transportation (TxDOT) and the City of Fort
Worth, TX, USA met to introduce and review the concept.
Following the initial meetings and discussions, conceptual plans
were developed and reviewed by different stakeholder groups
on a number of occasions. This was to ensure proper design and
to minimize the possibility of mistakes, misunderstandings, or

Transportation Engineer
(Ft. Lauderdale, FL)
Prepare technical reports and memoranda associated
with traffic engineering, transportation planning studies/
projects and traffic impact analyses.
Mail resume referencing job code# 520RK to
BCC Engineering, LLC, ATTN: Human Resources Manager,
6401 SW 87th Avenue, Suite 200, Miami, Florida 33173.

ITE Journal - August 2020

Table of Contents for the Digital Edition of ITE Journal - August 2020