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Full-Text Articles in Engineering

Concrete Bridge Deck Performance Data And Metrics For The State Of Oregon, Jael Wettach-Glosser Sep 2019

Concrete Bridge Deck Performance Data And Metrics For The State Of Oregon, Jael Wettach-Glosser

Dissertations and Theses

Bridge decks are a critical element of a bridge that support and distribute vehicle loads to the superstructure. Because of the requirements of this role, bridge decks are exposed to severe conditions that typically lead to structural deficiency in bridges which is both costly and disruptive. Therefore, to keep bridges and highways in good repair, developing optimal preservation decisions for concrete bridge decks is key. In order to develop effective performance monitoring and preservation schedules, the parameters affecting bridge deck deterioration need to be better understood.

With guidance from the literature and Oregon Department of Transportation (ODOT) personnel, two datasets …


Historical Changes In Lower Columbia River And Estuary Floods: A Numerical Study, Lumas Helaire, Stefan Talke, David A. Jay, Andrew Mahedy Sep 2019

Historical Changes In Lower Columbia River And Estuary Floods: A Numerical Study, Lumas Helaire, Stefan Talke, David A. Jay, Andrew Mahedy

Civil and Environmental Engineering Faculty Publications and Presentations

Over the past 150 years, the Lower Columbia River Estuary controlling depth has approximately doubled, the majority of historical wetlands and floodplain have been reclaimed, numerous infrastructure projects have altered and confined flow pathways, and significant natural and anthropogenic changes to the discharge hydrograph have occurred. To investigate the effect of these changes on tides, river slope, and flood water levels, we construct and validate numerical models that simulate flow over late nineteenth‐century and present‐day bathymetry. The models are validated using archival (1853–1877) and modern tide measurements throughout the Lower Columbia River Estuary and river stage measurements from the tidal …


Evaluation Of Low And High Frequency Dynamic Response For Condition Assessment Of Reinforced Concrete Structures, Ali Hafiz Aug 2019

Evaluation Of Low And High Frequency Dynamic Response For Condition Assessment Of Reinforced Concrete Structures, Ali Hafiz

Dissertations and Theses

Concrete is widely used for civil infrastructure structures and they experience deterioration and degradation due to aging, increases in the traffic loads, harsher environmental conditions, use of deicing chemicals, etc. Therefore, evaluating the integrity of reinforced concrete structures has become of increasing interest for infrastructure owners and managers. A number of non-destructive testing (NDT) and structural health monitoring (SHM) methods have been developed in recent decades to aid in evaluating structures and provide input for asset management. One family of these methods uses the dynamic response of a structural member: stress waves (high frequency) and structural vibrations (low frequency). Both …


Test Setup Design And Cyclic Evaluation Of Rocking Clt Wall And Floor Restoring Force Lateral System, Aaron Davis Smith Jul 2019

Test Setup Design And Cyclic Evaluation Of Rocking Clt Wall And Floor Restoring Force Lateral System, Aaron Davis Smith

Civil and Environmental Engineering Master's Project Reports

The introduction of the demand for mass timber buildings in areas with seismic hazards has called for new lateral systems. Lateral systems in mass timber building typically utilize a rocking shear wall with post-tensioned rods to provide system re-centering. These post-tensioned rods add axial load to the shear wall and potentially endure long term creep affects. Mass Timber buildings consist of cross laminated (clt) shear walls and floor slabs along with glulam beams. The flexural capacity of the CLT floor slabs along with dead load can provide an alternative source for the restoring force. This project developed a test setup …


The Quest For Model Uncertainty Quantification: A Hybrid Ensemble And Variational Data Assimilation Framework, Peyman Abbaszadeh, Hamid Moradkhani, Dacian Daescu Mar 2019

The Quest For Model Uncertainty Quantification: A Hybrid Ensemble And Variational Data Assimilation Framework, Peyman Abbaszadeh, Hamid Moradkhani, Dacian Daescu

Civil and Environmental Engineering Faculty Publications and Presentations

This article presents a novel approach to couple a deterministic four‐dimensional variational (4DVAR) assimilation method with the particle filter (PF) ensemble data assimilation system, to produce a robust approach for dual‐state‐parameter estimation. In our proposed method, the Hybrid Ensemble and Variational Data Assimilation framework for Environmental systems (HEAVEN), we characterize the model structural uncertainty in addition to model parameter and input uncertainties. The sequential PF is formulated within the 4DVAR system to design a computationally efficient feedback mechanism throughout the assimilation period. In this framework, the 4DVAR optimization produces the maximum a posteriori estimate of state variables at the beginning …


Seismic Behavior Of Screen Grid Core Insulated Concrete Form Walls, Anwer Sabah Mohammed Mohammed Mar 2019

Seismic Behavior Of Screen Grid Core Insulated Concrete Form Walls, Anwer Sabah Mohammed Mohammed

Dissertations and Theses

The use of the insulated concrete form (ICF) walls in residential buildings has increased over the past few decades. Much research has been conducted to evaluate the lateral strength of these walls by applying monotonic and cyclic loadings. In the current study, full-scale shake table experiments were employed to evaluate the in-plane behavior of four screen grid insulated concrete form (SGICF) walls. The first two wall specimens utilized dry fit insulated form blocks made from recycled expanded polystyrene granules that were bonded together with cement. When stacked, the cavities in the blocks formed a grid of cores that are evenly …


The Influence Of Shared Mobility And Transportation Policies On Vehicle Ownership, Edgar Bertini Ruas Nov 2018

The Influence Of Shared Mobility And Transportation Policies On Vehicle Ownership, Edgar Bertini Ruas

PSU Transportation Seminars

With the emergence of several new providers of shared mobility services, such as Uber, Biketown and Car2go, there has been the promise of changes to the traditional way of owning and using a vehicle. One potential consequence of the new mobility services is the reduction in vehicle ownership. At the same time, cities are trying to anticipate these changes by reducing the amount of space dedicated to parking. This thesis aims to asses the extent to which new shared mobility and transportation policy strategies (especially parking requirements and transit pass availability) relate to vehicle ownership among residents of multifamily dwellings. …


Webinar: Segmenting The Market For Transportation Demand Management Campaigns, Philip L. Winters, Amy Lester Nov 2018

Webinar: Segmenting The Market For Transportation Demand Management Campaigns, Philip L. Winters, Amy Lester

TREC Webinar Series

Social marketing seeks to develop and integrate marketing concepts with other approaches to influence behaviors that benefit individuals and communities for the greater social good. It is a useful transportation demand management (TDM) planning approach to promote travel behavior change. The purpose of this study was to explore a consumer market segmentation technique successfully used in Europe for its applicability to marketing efforts in the United States. Attitudinal and demographic data were collected from 1900 individuals in Florida, Oregon, and Virginia modeled after the European approach. Clustering analysis was applied to divide the sample into segments so that members of …


Scenarios For Adoption Of Autonomous Vehicle Technologies In Freight, Sabya Mishra Nov 2018

Scenarios For Adoption Of Autonomous Vehicle Technologies In Freight, Sabya Mishra

PSU Transportation Seminars

Innovation adoption research has largely ignored organizational adoption, and little work has been done to understand or predict the adoption of innovations by freight organizations. Among the existing innovation adoption theoretical and methodological approaches this seminar will explore which are most appropriate methods for freight organizational adoption. The seminar will present a disaggregate market penetration model for freight transportation organizations adopting connected autonomous vehicle (CAV) technology and demonstrate an application using a case study area in Memphis, TN. The seminar will highlight ongoing and future organizational adoption research for CAVs, and other innovations.


Driver Comprehension Of Permissive Right-Turns With A Flashing Yellow Arrow (Fya), Christopher Monsere, David Hurwitz Oct 2018

Driver Comprehension Of Permissive Right-Turns With A Flashing Yellow Arrow (Fya), Christopher Monsere, David Hurwitz

PSU Transportation Seminars

This research explored driver comprehension and behaviors with respect to right-turn signal displays with a focus on the Flashing Yellow Arrow (FYA) in a driving simulator and a comprehension survey. Flashing yellow arrows are used in place of other turn signals, such as solid green or flashing yellow or red circles, to indicate that drivers may turn after yielding to oncoming traffic. These turns are considered “permissive.” Turns where no conflicting traffic is present, such as those indicated with a green arrow, are “protected” turns. The flashing yellow arrow’s inclusion in the 2009 Manual on Uniform Traffic Control Devices sped …


Unobserved Heterogeneity And Spatial Correlation: Statistical And Econometric Analyses Of Heavy-Vehicle Hard Braking And Crash Frequency, Jason Anderson Oct 2018

Unobserved Heterogeneity And Spatial Correlation: Statistical And Econometric Analyses Of Heavy-Vehicle Hard Braking And Crash Frequency, Jason Anderson

PSU Transportation Seminars

In heavy-vehicles (a truck with a gross vehicle weight rating of greater than 10,000 pounds), a hard braking event is described as an event that prompts the vehicle’s “black box” to record an abrupt change in speed. More specifically, this occurs when the driver applies excess force to the vehicle’s brake. These hard braking events can then serve as a proxy for several factors, such as economic impacts, environmental impacts, and impacts on safety. In the context of the present study, being that approximately one-third of all heavy-vehicle-caused crashes in 2014 were attributed to faulty brakes, there is a need …


Modeling The Impact Of Traffic Conditions And Bicycle Facilities On Cyclists' On-Road Stress Levels, Àlvaro Caviedes, Miguel A. Figliozzi Oct 2018

Modeling The Impact Of Traffic Conditions And Bicycle Facilities On Cyclists' On-Road Stress Levels, Àlvaro Caviedes, Miguel A. Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

Past research efforts have shown that cyclists’ safety, stress, and comfort levels greatly affect the routes chosen by cyclists and cycling frequency. Some researchers have tried to categorize cyclists’ levels of traffic stress utilizing data that can be directly measured in the field, such as the number of motorized travel lanes, motorized vehicle travel speeds, and type of bicycle infrastructure. This research effort presents a novel approach: real-world, on-road measurements of physiological stress as cyclists travel across different types of bicycle facilities at peak and off-peak traffic times. By matching videos with stressful events, it was possible to observe the …


Reducing Exposures Traffic-Related Air Pollution And Urban Building Design, Elliott T. Gall, Linda George Sep 2018

Reducing Exposures Traffic-Related Air Pollution And Urban Building Design, Elliott T. Gall, Linda George

Mechanical and Materials Engineering Faculty Publications and Presentations

No abstract provided.


Advancing Bridge Technology, Task 10: Statistical Analysis And Modeling Of Us Concrete Highway Bridge Deck Performance -- Internal Final Report, Omar Ghonima, Thomas Schumacher, Avinash Unnikrishnan, Adam Fleischhacker Sep 2018

Advancing Bridge Technology, Task 10: Statistical Analysis And Modeling Of Us Concrete Highway Bridge Deck Performance -- Internal Final Report, Omar Ghonima, Thomas Schumacher, Avinash Unnikrishnan, Adam Fleischhacker

Civil and Environmental Engineering Faculty Publications and Presentations

Concrete highway bridge deck repairs represent the highest expense associated with bridge maintenance cost. In order to optimize such activities and use the available monies effectively, a solid understanding of the parameters that affect the performance of concrete bridge decks is critical. The National Bridge Inventory (NBI), perhaps the single-most comprehensive source of bridge information, gathers data on more than 600,000 bridges in all fifty states, the District of Columbia, and the Commonwealth of Puerto Rico. Focusing on concrete highway bridge deck performance, this research developed a nationwide database based on NBI data and other critical parameters that were computed …


Lateral Deformation Behavior Of Mass Timber Beam To Column Gravity Connection, Tyler James Williams Jul 2018

Lateral Deformation Behavior Of Mass Timber Beam To Column Gravity Connection, Tyler James Williams

Civil and Environmental Engineering Master's Project Reports

A beam-to-column connection consisting of glulam beam and column and cross laminated timber floor slab was developed and experimentally evaluated for use in buildings that are expected to undergo earthquake-­­induced lateral drift. The connection utilized a passive gap closure mechanism designed to allow beam rotations during lateral drift while minimizing residual separation between the beam and the column following an earthquake. Full scale cyclic experiments were used to validate the connection’s minimal rotational stiffness and demonstrate low damage performance for lateral drifts exceeding 4.5% drift. The connection exhibited no degradation in gravity load capacity throughout the imposed lateral deformations. An …


A 3d Model For Earthquake-Induced Liquefaction Triggering And Post-Liquefaction Response, Arash Khosravifar, Ahmed Elgamal, Jinchi Lu, John Li Jul 2018

A 3d Model For Earthquake-Induced Liquefaction Triggering And Post-Liquefaction Response, Arash Khosravifar, Ahmed Elgamal, Jinchi Lu, John Li

Civil and Environmental Engineering Faculty Publications and Presentations

A constitutive soil model that was originally developed to model liquefaction and cyclic mobility has been updated to comply with the established guidelines on the dependence of liquefaction triggering to the number of loading cycles, effective overburden stress (Kσ), and static shear stress (Kα). The model has been improved with new flow rules to better capture contraction and dilation in sands and has been implemented as PDMY03 in different computational platforms such as OpenSees finite-element, and FLAC and FLAC3D finite-difference frameworks. This paper presents the new modified framework of analysis and describes a guideline to calibrate the input parameters of …


Exploring The Determinants Of Vulnerable Road Users’ Crash Severity In State Roads, Álvaro Caviedes Jan 2018

Exploring The Determinants Of Vulnerable Road Users’ Crash Severity In State Roads, Álvaro Caviedes

PSU Transportation Seminars

Part of the Student Presentations from TRB

Pedestrians and bicyclists are the most vulnerable road users and suffer the most severe consequences when crashes take place. An extensive literature is available for crash severity in terms of driver safety, but fewer studies have explored non-motorized users’ crash severity. Furthermore, most research efforts have examined pedestrian and bicyclist crash severity in urban areas. This study focuses on state roads (mostly outside major urban areas) and aims to identify contributing risk factors of fatal and severe crashes involving pedestrians and bicyclists in state roads. The results seem to suggest that besides improvements …


The Transport Of Non-Spherical Particles In A Simulated Ocean Environment, Hannah Reed Jan 2018

The Transport Of Non-Spherical Particles In A Simulated Ocean Environment, Hannah Reed

REU Final Reports

Plastic particles contaminating the world’s oceans and accumulating in oceanic gyres has become a ubiquitous problem and the solution involving how to clean up the debris efficiently has still not been found. One particular issue is understanding where the greatest densities of debris may be. It is known that floating trash will tend to accumulate in large circular systems of ocean water called gyres, however these areas span thousands of miles of ocean. The present study aims to understand the transport of anisotropic particles in conditions similar to an oceanic environment using experimental methods in an effort to better predict …


Modified Design Procedures For Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Arash Khosravifar, Jonathan Nasr Jan 2018

Modified Design Procedures For Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Arash Khosravifar, Jonathan Nasr

Civil and Environmental Engineering Faculty Publications and Presentations

Effective-stress nonlinear dynamic analyses (NDA) were performed for piles in the liquefiable sloped ground to assess how inertia and liquefaction-induced lateral spreading combine in long- and short-duration motions. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of durations and amplitudes. The NDA results showed that the pile demands increased due to (a) longer duration shakings, and (b) liquefaction-induced lateral spreading compared to nonliquefied conditions. The NDA results were used to evaluate the accuracy of the equivalent static analysis (ESA) recommended by Caltrans/ODOT for estimating pile demands. Finally, the NDA results were …


Inertial And Liquefaction-Induced Kinematic Demands On A Pile-Supported Wharf: Physical Modeling, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough Jan 2018

Inertial And Liquefaction-Induced Kinematic Demands On A Pile-Supported Wharf: Physical Modeling, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough

Civil and Environmental Engineering Faculty Publications and Presentations

Results of a centrifuge test on a pile-supported wharf were used to investigate the time-, depth-, and row-dependent nature of kinematic and inertial loading on wharf piles in sloping rockfill. P-y models were calibrated against recorded bending moments in different piles and different depths. It was found that full kinematic demands and full superstructure inertia should be combined to estimate bending moments at pile head and shallow depths (less than 10 diameters below the ground surface). On the contrary, it was found that applying full kinematic demands alone was adequate to estimate pile bending moments at large depths (greater than …


The Effects Of Long-Duration Subduction Earthquakes On Inelastic Behavior Of Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Jonathan Nasr, Arash Khosravifar Jan 2018

The Effects Of Long-Duration Subduction Earthquakes On Inelastic Behavior Of Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Jonathan Nasr, Arash Khosravifar

Civil and Environmental Engineering Faculty Publications and Presentations

Effective-stress nonlinear dynamic analyses (NDA) were performed for a large-diameter reinforced concrete (RC) pile in multi-layered liquefiable sloped ground. The objective was to assess the effects of earthquake duration on the combination of inertia and liquefaction-induced lateral spreading. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of motion durations. The NDA results showed that the pile head displacements increased under liquefied conditions, compared to nonliquefied conditions, due to liquefaction-induced lateral spreading. The NDA results were used to develop a displacement-based equivalent static analysis (ESA) method that combines inertial and lateral spreading …


Safety Effectiveness Of Pedestrian Crossing Treatments, Christopher Monsere Oct 2017

Safety Effectiveness Of Pedestrian Crossing Treatments, Christopher Monsere

PSU Transportation Seminars

Over the last decade, the transportation agencies in Oregon have systematically enhanced many pedestrian crossings at mid-block locations with Rectangular Rapid Flashing Beacons (RRFBs), Flashing Yellow Beacons (Flash), and high visibility crosswalk markings (Hi-Vis). Enhancements often included the installation of refuge medians. This study explored the safety performance of these enhanced crossings, categorized by enhancement type. Data were collected on 191 crossings that included installation year, geometric features, surrounding land use, traffic volumes, and the number of crashes. Because pedestrian volume at the locations was unavailable, a pedestrian activity level variable was developed. Target crashes for analysis were identified as …


Building Intelligence In The Automated Traffic Signal Performance Measures With Advanced Data Analytics, Tingting Huang, Subhadipto Poddar, Chris Aguilar, Anuj Sharma, Edward J. Smaglik, Sirisha Kothuri, Peter Koonce Aug 2017

Building Intelligence In The Automated Traffic Signal Performance Measures With Advanced Data Analytics, Tingting Huang, Subhadipto Poddar, Chris Aguilar, Anuj Sharma, Edward J. Smaglik, Sirisha Kothuri, Peter Koonce

Civil and Environmental Engineering Faculty Publications and Presentations

Automated traffic signal performance measures (ATSPMs) are an effort to equip traffic signal controllers with high-resolution data-logging capabilities and utilize this data to generate performance measures. These measures allow practitioners to improve operations as well as to maintain and operate their systems in a safe and efficient manner. Although these measures have changed the way that operators manage their systems, several shortcomings of the tool, identified by talking with signal operators, are a lack of data quality control and the extent of resources required to properly use the tool for system-wide management. To address these shortcomings, intelligent traffic signal performance …


A Simulator-Based Analysis Of Engineering Treatments For Right-Hook Bicycle Crashes At Signalized Intersections, Jennifer Warner, David S. Hurwitz, Christopher M. Monsere, Kayla Fleskes Jul 2017

A Simulator-Based Analysis Of Engineering Treatments For Right-Hook Bicycle Crashes At Signalized Intersections, Jennifer Warner, David S. Hurwitz, Christopher M. Monsere, Kayla Fleskes

Civil and Environmental Engineering Faculty Publications and Presentations

A right-hook crash is a crash between a right-turning motor vehicle and an adjacent through-moving bicycle. At signalized intersections, these crashes can occur during any portion of the green interval when conflicting bicycles and vehicles are moving concurrently. The objective of this research was to evaluate the effectiveness of four types of engineering countermeasures – regulatory signage, intersection pavement marking, smaller curb radius, and protected intersection design – at modifying driver behaviors that are known contributing factors in these crashes. This research focused on right-hook crashes that occur during the latter stage of the circular green indication at signalized intersections …


Dynamic Evaluation Of Transportation Structures With Ipod-Based Data Acquisition, Charles Riley Apr 2017

Dynamic Evaluation Of Transportation Structures With Ipod-Based Data Acquisition, Charles Riley

TREC Final Reports

This grant supported coursework and laboratory development and expanded research capacity, promoting (a) innovative learning activities that expose students to cutting-edge methods of bridge structural health and behavior monitoring and (b) research by our growing group of graduate students using developing technologies (specifically, shake tables and iPods with on-board accelerometers). As transportation infrastructure reaches and exceeds its design life, engineering efforts are turning to evaluation, rehabilitation and repair. Accurately assessing structures to determine their future performance and remaining life is becoming a primary job function for many civil engineers.

As part of this project, graduate students worked with the PI …


Design For An Aging Population, Trygve Faste, Kiersten Muenchinger Apr 2017

Design For An Aging Population, Trygve Faste, Kiersten Muenchinger

TREC Final Reports

Older Americans are increasing in numbers and addressing their needs through better public transportation design will improve their quality of life. This study sought to increase understanding of the obstacles faced by people with impairments in vision, hearing and/or mobility, which are common issues for older people, and generate physical product solutions. The research was conducted to conceptualize products, structures and services to reduce or eliminate these obstacles.

With a focus on the Eugene, OR, public bus system, elderly riders were surveyed and interviewed. Designers rode on buses noting what worked well and where problems arose. Five ride-along observations of …


An Analytical System For Determining Disciplinary Vocabulary For Data-Driven Learning: An Example From Civil Engineering, Philippa Jean Otto Mar 2017

An Analytical System For Determining Disciplinary Vocabulary For Data-Driven Learning: An Example From Civil Engineering, Philippa Jean Otto

Dissertations and Theses

Data-driven learning (DDL), an inductive teaching approach in which students learn through corpus interaction, has gained recent traction as way to teach specialized vocabulary in English for Specific Purposes (ESP) classes. There is little research, however, that addresses how to choose specialized vocabulary for teaching with DDL.

This study addressed this gap in research by exploring the potential of a three-part analytical, corpus-based system for determining vocabulary to teach with DDL for a specific context of language use. This system included (1) identifying words that were significantly more frequent in a specialized expert corpus than in a corpus of general …


Seismic Retrofit Case Study Of Reinforced Concrete Bridges With Buckling Restrained Braces, Michael K. Miotke Jan 2017

Seismic Retrofit Case Study Of Reinforced Concrete Bridges With Buckling Restrained Braces, Michael K. Miotke

Civil and Environmental Engineering Master's Project Reports

Many highway bridges in Oregon have been designed with minimal considerations for seismic hazard and are in need of retrofit. Although buckling restrained braces (BRBs) are not necessarily a new concept, using them to seismically retrofit bridges is. This case study investigates the BRB retrofit concept as compared to traditional retrofit measures for a sample of typical vulnerable bridges in Oregon. The objectives of evaluating these cases were to determine the feasibility of the concept both in terms of performance as well as construction costs. This study builds on the ongoing research at Portland State University into the development of …


Seismic Evaluation Of 196kv Transformer Bushings, Joanne R. Shields Jan 2017

Seismic Evaluation Of 196kv Transformer Bushings, Joanne R. Shields

Civil and Environmental Engineering Master's Project Reports

Transformer bushings have shown to have an unsatisfactory performance during earthquakes and have therefore been chosen for further testing. How the bushings fail, and how this failure can be prevented has been analyzed. Two used 196 kV bushings made by General Electric were chosen for seismic testing at the iSTAR laboratory located at Portland State University in Portland, OR. The multiple objectives that brought about these tests were: to determine how the bushings failed due to gasket extrusion at the porcelain-flange connection and to verify that the failure was due to pure tipping and not sliding, to determine the damping …


Feasibility Determination Guide For The Road Diet Plus: A Five/Four-Lane To Two-Lane Road Diet, Michael Williams Jan 2017

Feasibility Determination Guide For The Road Diet Plus: A Five/Four-Lane To Two-Lane Road Diet, Michael Williams

Civil and Environmental Engineering Master's Project Reports

Road diets are a popular tool for corridor improvement. Road diets are normally defined as the conversion of a four-lane undivided road to a three-lane undivided road made up of two through lanes separated by a center two-way-left-turn-lane (known as a TWLTL). This new configuration has similar vehicular capacity, greater safety and frees up right-of-way for other uses.

This work examines the possibility of going one step, or one lane, further. What is the possibility of reducing five- or four-lane roads to two-lanes? If this is possible, what are the corridor characteristics within which this process would be feasible?

The …