QE | Parallel flow intersection

The Parallel Flow Intersection
(U.S. Patent No. 7,135,989)

The parallel flow intersection or paraflow is a new high capacity signalized
intersection that can cost less and reduce impacts over other
intersection or interchange alternatives.

1	Paraflow intersection can have as much as 90% less delay than a traditional intersection
2	Cost to build the paraflow intersection is substantially less than an interchange
3	Paraflow intersection fewer property and environmental impacts than an interchange
4	Improves air quality by reducing congestion over traditional designs
5	Paraflow intersection is potentially safer than traditional intersections with four fewer crossing conflicts than a traditional intersection and all turn movements are protected
6	Paraflow intersection has faster build time to convert existing intersection than with other nontraditional designs since 90% of the work is outside existing roadway
7	The paraflow is more intuitive to drive than other nontraditional designs since drivers turn left at the main junction (just not through the main junction)
8	Traditional diamond interchanges with freeway overhead can be converted to paraflow diamond inexpensively by placing bypass lanes behind bridge piers (by replacing slope protection with retaining wall)
9	3-phase paraflow/continuous flow intersection (CFI) hybrid can be built to avoid corner impacts with one intersection leg as a paraflow and the opposite leg a CFI
10	Paraflow intersection geometry is adaptable and can be tailored to fit the site

"The Parallel Flow Intersection: A New Two-Phase Signal Alternative" ITE Journal, October 2007 download (6MB)

Ohio Transportation Engineers Conference PowerPoint Presentation, October 2006 coming soon

"The Parallel Flow Intersection: A Modern High Capacity Traffic Intersection" white paper, February 2006 download (3MB)

Schematic line diagram for 2-phase 4-leg paraflow intersection
with conflict points and basic signal phasing

Work necessary to convert an existing intersection to a paraflow is almost entirely on the outside resulting
in minimal inconvenience to the public, quicker construction and a safer work zone