High Volume Intersection Study

High Volume Intersection Study


High Volume Intersection Study: http://www.compassidaho.org/documen...ol1_Implementation_Guidelines_Final_May30.pdf

Operational Effects of Signalized Superstreets: http://repository.lib.ncsu.edu/ir/bitstream/1840.16/6112/1/etd.pdf


Introduction

The Community Planning Association of Southwest Idaho (COMPASS) adopted Communities in Motion: Regional Long-Range Transportation Plan 2030 (CIM) in August 2006. COMPASS, as a part of its metropolitan planning organization (MPO) responsibilities, developed the plan for the region with the assistance of its member agencies. The High Volume Intersection Study (HVIS) was initiated in response to findings and policy statements that appear in CIM.

A key objective of the HVIS is to develop guidelines and recommendations for implementing innovative intersection designs in the region. The project team prepared this report as a means of helping COMPASS achieve that objective.

The recommendations in this report are suitable for use by highway agencies, cities, counties, and by other agencies/jurisdictions throughout the COMPASS region. This report’s recommendations will help land use agencies establish standards for innovative intersection types, which will facilitate implementation of innovative intersections throughout the COMPASS region. Information from the report may also be useful for updating the regional travel demand models.[/QUOTE]




1.1. What is an “Innovative Intersection�

For this document, a conventional high-capacity intersection typically would have a dedicated pocket for right turns, 2-3 through lanes per direction, and double left-turn pockets with left-turn arrows. This results in a 4-phase signal (a left phase and a through phase for the two directions of one street, and the same on the cross street). An innovative intersection is generally defined as any at-grade design concept that is able to reduce the number of phases at the main intersection, thereby increasing the efficiency and capacity of the signal. In most cases this is accomplished by rerouting left turns at a point well ahead of the main intersection, or to require the driver to do something unusual, such as first go through, then make a U-turn, and finally a right turn.




Why are innovative intersections uncommon?

• Lack of industry awareness – many are
relatively new ideas.

• Though the cost/benefit ratio is often very
good, they still typically cost more than a
conventional intersection.

• In some cases they are out of context or
don’t work in a particular location.

• Usually requires turning movements that
differ from typical driver expectations.

• Problems at conventional intersections have
historically been tolerable in spite of their
inefficiency.




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M II A II R II K said:

High Volume Intersection Study

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IMO the first picture kinda looks like a cleaner, 4 lane version of spaghetti junction

These intersections seem perfect for booming suburban Boise, or any place that has vast swaths of flat land, no interest in creating urban places, and zero pedestrians.

It's similar to Telegraph Road. Michigan Lefts, Jughandles and wide median reduces the number of red lights for through traffic. But it's the great American model of how to supersize suburbia. You need a lot of land for proper superstreets.

If the Gardiner Expressway were to ever come down, like it or not, we'd have to explore some of these alternative intersections to handle the traffic flow. Hell, there are places in the inner-suburbs where these designs could work.

Such ideas are simply a disgusting waste of time.

Ah, automobile planning at its finest. All that matters is the number of cars that can pass through a given intersection in a given amount of time. Increasing the "efficiency" (which is none other than the vehicular capacity) of intersections will eliminate traffic congestion, and will turn the city into a transportation utopia!

Seriously though, our intersections between major suburban arterials could use some improvement. Extended right-turn lanes would allow buses to proceed to their stops quicker (rather than waiting a full cycle before even arriving at the stop) and result in significantly reduced travel time at negligible cost.

Well, the diverging diamond is the perfect alternative to a Parclo, as the majority of traffic coming off of the freeway eithier freeflows past the traffic light's, or theres enough room to prevent a backlog of cars onto the highway.

well making a left turn at a major intersection is always a pain and is quite dangerous and inefficient. It is likely one of the few ways even a good driver can get killed.

I suggest that super busy intersections in the suburban areas restrict left turns only when a left turn signal comes on. It greatly increases the safety of an intersection.