Reports

This study consists of four main elements: a comprehensive literature review examining the effects of narrower travel lanes and other geometric design feature on speed, safety, and other transportation impacts; an in-depth survey of the minimum lane width policies and practices adopted by Vtrans, ODOT, Catlrans, FDOT, and DelDOT;  a survey of AASHTO Committee on Design members regarding their policies and practices; and statistical analyses of various factors, including lane width, geometric features, roadside characteristics, block length, and AADT, on 85th and 95th percentile speeds and non-intersection crash counts. The data for analysis were collected for 320 urban arterial sections and 61 rural arterial sections throughout the state of Utah, encompassing all types of UDOT roads. All parts of this study support the conclusion that Utah should reduce lane width standards from 12 feet in urbanized areas to 11 to 10 feet.

A "polycentric" region consists of a network of compact development centers connected by high quality transit. Rather than continuing the expanse of low-density development radiating from an urban core, investments can be concentrated on central nodes and transit connections. This development pattern is very popular in Europe and is linked to significant benefits. An analysis of the data demonstrates that people living in centers make fewer and shorter automobile trips, take transit more, walk more, and bike less. The study also comes to the conclusion that trip tours, a sequence of trips that begin and end at home, are far more efficient when associated with a center compared to ones that avoid centers completely. Finally, the report identified strategies to promote polycentric development within the Wasatch Front. It recommends 10,000-25,000 activity density (16-40 per acre; may vary by center types), a minimum of 150 intersections/square mile, over 60% of four-way intersections, over 60 transit stops/square mile, and a minimum 30% of regional job accessibility within 30 minutes by transit.

Transportation continues to be a huge source of greenhouse gas (GHG) emissions. However, people who use public transit regularly emit significantly less GHG emissions than people who drive. In 2018, the average person riding transit emitted 55% less GHGs per mile than if they were to drive alone. People who live in areas with efficient land use planning also emit far less GHG emissions then those who live in sprawling areas due to shorter trip distances. Transit agencies are becoming increasingly environmentally aware and transit emissions have fallen over the last 15 years. However, Covid 19 and patterns of decreasing ridership threaten to reverse this trend. This study seeks to quantify the full lifecycle of transportation fuels to ensure that transit continues to be sustainable in the future. The study analyzes three main sources of GHG emissions as follows;  Direct CO2e emissions occurred at the vehicle, indirect CO2e occurred at power plants & hydrogen production facilities, and upstream CO2e from fuel production & distribution.

TRAX light rail service to the University provides a model for which the effects of transit on redevelopment, energy consumption, and air pollution can be quantified. This study seeks to update a report previously published in 2014 by Ewing, Tian, and Spain, which found that the provision of light rail transit on the 400/500 S corridor between downtown Salt Lake City and the University of Utah reduced automobile traffic in the corridor by approximately 10,000 vehicles per day (VPD). The original report assesses TRAX’s short-term impacts, this report assesses long-term impacts.

This study seeks to quantify the short-term and long-term effects of implementing a new Provo-Orem Bus Rapid Transit (BRT) line on traffic volumes, transit ridership, nearby land use development, land market value, trip generation, automobile traffic speed, traffic safety, parking supply, and vehicle emission reduction, providing quantitative data that can be used for future transportation policies aimed at reducing traffic impacts. The study concludes that BRT was successful at increasing traffic flow, reducing crashes, and reducing carbon emissions along the corridor studied. 

Measuring Gentrification

To measure gentrification, rather than using single indicators of gentrification such as income levels, shares of minority populations, rent levels, and educational attainment, this study uses Principal Component Analysis (PCA) to combine the four most commonly used measures of gentrification into one cohesive measure or index that describes the socio-economic status of a given area, and when used over time shows changes in such status. In this study, the PCA values for each Census tract in Salt Lake County for years 2011, 2016, and 2019 were calculated using the four variables that are most frequently associated with gentrification and used to measure it: percent of Hispanic population, gross rent, median household income, and the percent of residents with a college degree or higher.

Measuring Displacement

This study defines displacement as the moving out of the low-income, minority (Latino) households from the TRAX light rail corridor and simultaneous moving in of higher income, white households. The study measured migration patterns for each set of two consecutive years between 2015 and 2022. To measure outmigration the study simply recorded the number of households that moved out of the 0.5-mile buffer around TRAX stations between two consecutive years and to measure in-migration the study recorded the number of households that moved into the buffer between the same two consecutive years. 

Affordable Housing Policies

As it is a well-known fact that low-income households are the most avid transit users and often use it for their daily transportation needs, the study looked at the strategies and policies that five other transit operators and cities used to incentivize the production of affordable housing near transit. It was found that in all instances, the municipalities, and not the transit agencies, were the ones responsible for implementing the policies and strategies designed to incentivize the production of affordable (income restricted) housing units. Cities in more liberal states rely on inclusionary housing policies which require all new development to either set aside a certain percentage of units as affordable or pay an in-lieu fee, cities in states that explicitly do not allow such policies rely mostly on incentives in hope that developers will opt for a density or height bonus in exchange for providing some of the units (usually about 10%) for low-income households. The number and type of policies and strategies used by the five interviewed cities varies greatly but none of the cities are on track to fulfilling their affordable housing commitments or closing the housing affordability gap.

This report aims to examine how airports can function as connected activity centers. This research is important because airports have significant influence on urban form and economic development. Lack of integration in airport and regional planning often fails to leverage the unique potential of airports as an economic development tool. Current planning practices do not typically address the influence of airports on urban form and economic development, and there is a lack of research to guide practice. This report is intended to help counteract this tendency by identifying best practices for regional airport systems, analyzing various development scenarios, and presenting the results to aid and abet economic development efforts. 

The United States Department of Housing and Urban Development (HUD)’s measure of housing affordability is the most widely used and the most conventional measure of housing affordability. According to the HUD measure, total housing costs at or below 30% of gross annual income are affordable. The HUD has no way of knowing since transportation costs fall outside its purview and regulations. But transportation costs, after housing, is the second biggest expenses in the budgets of most American households particularly for those settled along the urban fringe. Less costly alternatives to automobile travel, particularly public transit, are typically much less accessible and thus largely impractical in suburban and exurban locations relative to central cities. This study seeks to determine whether HUD rental assistance programs provide “affordable housing” when transportation costs are factored in.

This study seeks to first identify how micromobility usage affects public transportation ridership in Salt Lake County, Utah, as a case region, as well as find key built environment factors (e.g., activity density, job-pop balance, intersection density, and distance to transit, etc.) associated with their integrated use. Then, the study will conduct intercept surveys with micromobility users around public transit stations (rail) to find users' sociodemographic information and intention to use micromobility, which is then used to find detailed micro-level factors that facilitate integrated use. This research aims to provide guidelines and policy recommendations for the Utah transit agencies to boost public transportation ridership by (1) identifying the overall impact of micromobility on public transit ridership and key built environment factors and (2) conducting intercept surveys to find the determinants of integrated usage between micromobility and public transit, connecting first and last mile by identifying users' sociodemographic characteristics and their intentions to use micromobility as a feeder mode for public transportation.

This report presents two case studies to be compared, the first of which is Orenco Station, on the west side of the Portland metropolitan area in the suburban city of Hillsboro, OR. Orenco Station may be the most well-known and lauded freestanding TOD (as opposed to infill TOD) in the nation. The second, is Station Park, a mixed-use development abutting a commuter rail station on the north size of the Salt Lake City region in the suburban city of Farmington, UT. Station Park labels itself a TOD, but projects as a giant shopping center with a commuter rail station at one corner and a pedestrian pocket in the center.

This report was created to understand better what incentives, policies, and tools the cities of Lehi, Ogden, Orem, Park City, Provo, Salt Lake City, Sandy, South Salt Lake, West Jordan, and West Valley City use to stimulate the development of affordable housing. Across the ten municipalities, the study found common themes and goals related to providing a range of housing types, styles, sizes, and price levels, including creating the “missing middle” forms of housing like duplexes, triplexes, condominiums, and townhomes through infill housing in walkable neighborhoods. Reinvesting in older neighborhoods and rehabilitating current housing stock were also common goals, especially in cities where housing prices are more affordable. Supplying housing that serves different life cycle stages and conditions, including students, seniors, people with disabilities, and others requiring specialized facilities, was a common goal. It was also found that the tools and strategies municipalities employ reflects each city’s unique preferences and political will for affordable housing that can be influenced by public opinion. 

Conventional four-step travel demand models are used by nearly all metropolitan planning organizations (MPOs), state departments of transportation, and local planning agencies, as the basis for long-range transportation planning in the United States. States. In the simplest terms, the four-step model proceeds from trip generation, to trip distribution, to mode choice, and finally to route assignment. However, the four-step model fails to account for D variables, which are characteristics of the built environment that are known to affect travel behavior. The Ds are development density, land use diversity, street network design, destination accessibility, and distance to transit. This report develops a vehicle ownership model (car shedding model), an intrazonal travel model (internal capture model), and a mode choice model that consider all of the D variables based on household travel surveys and built environmental data for 32, 31, and 29 regions, respectively, validates the models, and demonstrates that the models have far better predictive accuracy than current models.

This study seeks to quantify the effect of the University TRAX light-rail line on traffic near the University of Utah. Data collected by the Utah Department of Transportation showed that traffic near the university has fallen to levels not seen since the 1980s, even as the number of students, faculty and staff at the university has increased. A survey conducted in 2005 found that nearly a quarter of students, faculty and staff at the university used transit as a primary mode of transportation to and from campus. This study's aim is to quantify quantify the associated savings on energy consumption, air pollution, and parking costs, that TRAX light rail generates, and to compare cost savings to transit subsidies.

Across the nation, the debate over metropolitan sprawl and its impacts continues. In the year 2000, Smart Growth America (SGA) and the U.S. Environmental Protection Agency (EPA) sought to raise the level of this debate by sponsoring groundbreaking research on sprawl and its quality-of-life consequences (Ewing et al. 2002; Ewing et al. 2003a, 2003b, 2003c). Chapter one begins by updating these indices to 2010. Chapter two develops more refined versions of the indices that incorporate more measures of the built environment. Chapter three develops four metropolitan sprawl indices; development density, land use mix, population and employment centering, and street accessibility. Chapter four conducts one of the first longitudinal analysis of sprawl to see which areas are sprawling more over time, and which are sprawling less or becoming more compact. And chapter five develops compactness indices for census tracts within metropolitan areas.

Guidelines for trip and parking generation in the United States come mainly from the Institute of Transportation Engineers (ITE). This study aims to determine how many fewer vehicle trips are generated at transit-oriented developments (TODs), and how much less parking is required at TODs, than ITE guidelines would suggest. This study follows a previous study done on five TOD's across the nation. The sixth subject of study is Orenco Station TOD, one of the most acclaimed TOD's in the US, and Station Park, a transit-adjacent development (TAD) which contains some mixed-use development next to a train station. Orenco Station creates significantly less demand for parking and driving than do conventional suburban developments. Peak parking demand is less than one half the parking supply guideline in the ITE guideline. Also, vehicle trip generation rates are about half what is suggested in the ITE guideline.

Optimal land use around transit stations is a debated topic. Currently, many transit officials opt to build park-and-ride lots over active uses such as housing or retail. While park-and-ride lots are frequently used to maximize transit ridership in the short term, many wonder if they are best to maximize transit ridership in the long term. And even when the land is developed, officials usually assume that transit-oriented development (TOD) needs the same amount of parking as park-and-ride lots do. This study seeks to find the answer to these paradigms by examining five TOD's using the most robust methodology known to date. The sample of TODs in this study consists of Redmond TOD in the Seattle region, Rhode Island Row in the Washington, D.C. region, Fruitvale Village in the San Francisco/Oakland region, Englewood TOD in the Denver region, and Wilshire/Vermont in the Los Angeles region. These TOD's are exemplarily in all the D variables, which are often used to research developments. The D variables are as follows; diverse land use, minimal distance to transit, destination accessible via transit, accessible to the demographics that need transit the most, and dense residential use. This study finds that TOD's create significantly less demand for parking than conventional suburban developments, and that peak parking demand is less than half of what is standard with only one exception. 

Ewing (1999) defines traffic calming as ‘changes in street alignment, installation of barriers, and other physical measures to reduce traffic speeds and cut-through volumes, in the interest of street safety, livability, and other public purposes.’ Traffic calming is required on streets bordered by land uses that tend to generate pedestrian traffic, like commercial, residential, office areas and a mix of these. To provide a safe walking environment for the pedestrian, various traffic calming interventions, both physical (e.g., lateral shifts, chicanes, bulb-outs) and non-physical (e.g., speed limit signs, speed feedback signs), are installed at such intersection points of vehicles and pedestrians. Various studies observe that there is a significant decrease in crashes when traffic calming measures are implemented. This study seeks to quantify to what extend traffic calming measures reduce speeds and crashes in Salt Lake City.

Compact development that is dense, diverse, well-designed, etc. produces fewer vehicle miles traveled (VMT) than sprawling development. But compact development also concentrates origins and destinations. No one has yet determined, using credible urban form metrics and credible congestion data, the net effect of these countervailing forces on area-wide congestion. Using compactness/sprawl metrics developed for the National Institutes of Health, and congestion data from the Texas Transportation Institute’s (TTI’s) Urban Mobility Scorecard Annual Report database, this study seeks to determine which opposing point of view of sprawl and congestion is correct. It does so by (1) measuring compactness, congestion, and control variables using the best national data available for U.S. urbanized areas and (2) relating these variables to one another using multivariate methods to determine whether compactness is positively or negatively related to congestion. Our model (and earlier studies by the same authors) suggest that an increase in compactness reduces the amount of driving people do, but also concentrates the driving in smaller areas. This analysis does not support the idea that sprawl acts as a “traffic safety valve,” as some have claimed. However, it also does not support the reverse idea that compact development offers a one-stop solution to congestion, as others have claimed. 

A large body of research examines the effect of transit service on vehicle miles traveled (VMT). Most of this research focuses on direct effects, whereby travelers shift from driving to riding transit. There is also evidence that transit can have indirect effects on VMT via changes in land use and other secondary factors. However, little research has been done that focuses on the indirect effects of transit on VMT. The overall objective of this project is to illuminate the complex interrelationship between transit and land use patterns in a way that will help transit agencies to better foster compact development and to better understand their contribution to, and the benefit they receive from, compact development.