Elizabeth K. Burns

Cycling to Work in Phoenix: Route Choice, Travel Behavior, and Commuter Characteristics

Through a survey of expert cyclists, the relationship between the actual routes cyclists traveled and existing street conditions was documented, and bicycle commuters of the Phoenix metropolitan area were profiled. Data were collected on individual commuting routes between home and work. Additional data collected include age and gender characteristics. Frequency analysis in a geographic information system compared the number of common street segments among actual and alternative routes to determine cyclists’ use of existing street facilities. Findings are reported for actual routes compared with shortest distance, shortest time, and safest route alternatives on street facilities between the same origin and destination. Spatial analysis identified local gaps in arterial street bicycle facilities at municipal boundaries. These findings include evidence that cyclists adjust their routes to use current street bicycle facilities, and suggest that policy makers should concentrate on linking bicycle facilities across jurisdictions.

The Size and Shape of Phoenix’s Urban Fringe:

Annual changes in the amount and location of residential fringe development in metropolitan Phoenix are tracked from 1990 to 1998 using local records of housing completions. New development covered a wide geographic area in 1990 but became more geographically concentrated with time. Metropolitan Phoenix is organized into five belts: (1) an outer rural zone, (2) an area of pioneer settlement where the construction of single-family housing began in 1990, (3) a peak zone of intensive development, (4) a zone of infill, and (5) a built-up area where little new construction occurs. Multiple-family housing construction occurs primarily in the infill zone. Between 1995 and 1998, new home construction moved outward at the pace of almost one-half mile per year to an average distance of 18.94 miles from the metropolitan center. Planners can use information about the size, shape, type, and timing of urban fringe development to anticipate infrastructure and service needs.

EVALUATION OF AN ALTERNATIVE TRAFFIC LIGHT CHANGE ANTICIPATION SYSTEM

A driving simulator was used to study the efficacy of an alternative signal phasing program. The new Traffic Light Change Anticipation System (TLCAS) utilizes a flashing amber in conjunction with a solid green indication to warn drivers of the impending onset of the solid amber indication. This new program was expected to provide drivers with additional information with which to make safe stopping or crossing decisions, and reduce behaviour associated with increased accident rates at signalized intersections. Additionally, a new measure of first response variability was introduced to evaluate the effect of the new program on driver behavior. The results indicated that the new system has the ability to reduce the number of red light violations. Of the 1148 target intersections, 43 violations were recorded for the regular program compared to 9 for the TLCAS program. The severity of decelerations was also impacted. The regular program displayed average maximum decelerations of 3.1 m/sec2 compared to 2.5 m/sec2 for the TLCAS program. However, the TLCAS program showed an increased variability in first response five times larger than the regular program. This finding, in conjunction with traditional measures, indicates that the new system performs comparably to an increased amber duration by increasing the potential for conflicting decisions between successive drivers approaching an intersection. Altogether, the results suggest that this alternative signal phasing program would not improve intersection safety. The findings also suggest that further study of the longitudinal behavior after the introduction of a TLCAS program may be warranted. Specifically, future studies should examine whether subjects engage in appropriate adaptive changes when confronted with a solid amber period warning after becoming familiar with the TLCAS.

Simulator Evaluation of Green and Flashing Amber Signal Phasing

A research study conducted to evaluate the efficacy of flashing amber signal phasing is reported. Flashing amber, which is set to overlap with the green indication a few seconds before the onset of solid amber, is a form of time reference aid used to warn drivers of an impending onset of amber. The time reference aid is a concept predicated on the principle that driver decisions will be easier and more predictable if drivers have advance information that allows them to predict the onset of amber. The evaluation of the flashing amber method showed that its implementation has the potential to reduce red-light violations, severity of maximum decelerations, and kinematically defined inappropriate stop or cross decisions. However, the data also showed that compared with the regular signal phasing, the flashing amber phasing increased the size of the indecision zone, a mechanism usually responsible for increased rear-end collisions. A measure not previously used in literature was introduced to compare the regular and the experimental signal phasing. This measure, which analyzes first-response time variability in relation to the indecision zone, predicted that increased rear-end collisions might be expected as a result of implementation of the flashing amber signal phasing. Generally, the results suggest that the implementation of a flashing amber signal phasing would not significantly increase intersection safety despite the notion that it would improve driver anticipation of the onset of solid amber.

Job Linkages in Inner- City Phoenix.

Current urban policy stresses the creation of a sustainable economic base in the inner city. It is assumed that increasing the number and range of jobs in the inner city will result in employment opportunities for disadvantaged local residents. This paper explores the linkage between inner-city employment and inner-city residence in Phoenix, Arizona, using the 1995 Maricopa County Trip Reduction Survey. Results indicate that only 15% of the employees of large businesses in inner-city Phoenix were residents of nearby neighborhoods. Stronger workplace-residence linkages were found in personal services, agricultural activities, hotels, and restaurants. Extremely weak linkages occurred in transportation-related activities at the local airport, communications and public utilities, and financial institutions. Few inner-city residents were employed in inner-city governmental activities. Occupational profiles with the strongest ties to inner-city residents were those oriented toward manufacturing tasks and those ...

Suitability of commuting by bicycle to Arizona Elementary Schools

Purpose. To determine the biking suitability (i.e., bikeability) of and prevalence of biking in 14 elementary schools representing two extremes of bused students (2.4% vs. 53.6%). Methods. Street segments (within 0.25-mile radius of school) were scored for bikeability. Bikes in racks per school student population established biking prevalence. Mann-Whitney U-test compared bikeability and prevalence of biking between groups. Results. A total of 12.5 ±2.2 streets per school were assessed. Thirteen schools scored very good (<3.0) and one scored fair (4.0–4.9). Median bikeability score was 0.69 for the low-busing schools and 0.53 for the high-busing schools (nonsignificant). Median biking prevalence was 3.1% in the low-busing schools and 1.3% in the high-busing schools (p < .05). Conclusion. Streets surrounding schools were adequate for biking. Biking prevalence was significantly higher in low-busing schools but was relatively low in both low- and high-busing schools. Other factors, including intraindividual, social, school, and community, likely contribute to choice of biking to school.

Application of a Walking Suitability Assessment to the Immediate Built Environment Surrounding Elementary Schools

This study examines the usefulness of applying a walking suitability assessment to a specific geographic area surrounding elementary schools. Streets within a 0.25-mile radius were measured to create a summary walking suitability score for seven schools from high-busing strata and seven from low-busing strata. Summary walking suitability scores were calculated for each school. A Mann—Whitney U test was conducted to determine any differences in scores between the high- and low-busing schools. The median walking suitability score was 3.7 (a good rating); the 25th percentile score was 2.9 (very good), and the 75th was 22.3 (poor). No statistical differences existed between busing strata. Walking suitability is an important consideration when examining the feasibility of walk-to-school programs within school settings; however, it might not be the main factor limiting childrens active commuting to school. Several aspects of the environment were captured that researchers, practitioners, school personnel, and transportation experts may deem useful.

Population density and land consumption trends in the metropolitan southwest

Abstract A gap exists between the developers of urban density gradient and land use models and applied researchers interested in understanding population density and land consumption trends. Simplifying model assumptions, lack of data, and local development patterns limit the usefulness of model insights for understanding specific regional and metropolitan contexts. This paper discusses the problems of developing an urban time series, using the regional context of Southwestern metropolitan areas, and specifically. Phoenix, Arizona, to emphasize issues of urban boundary measurement, microcomputer calculation, and contrasting local model assumptions. We conclude by addressing, the value of linking planning practice and current urban modeling research through similar comparative, applied studies using multiple data sources.

Vance's Commuting Analysis: An Application in Tempe, Arizona

In a 1960 study of Natick, Massachusetts, James E. Vance, Jr., showed how this Boston suburb’s character evolved as intraurban transportation and local employers’ labor needs changed. His analysis relied on two concepts: a community’s laborshed, the area from which employees are drawn, and its employment field, the area in which residents work. This Tempe, Arizona, study demonstrates the applicability of Vance’s concepts to present-day inner suburbs in Southwestern metropolitan areas using two modem procedures, a geographic information system analysis and sampling from employee commuting surveys collected by the Maricopa County Regional Travel Reduction Program. While data availability may limit comparative studies, Tempe’s 1990 extensive laborshed and smaller employment field reveal that this inner suburb is both a bedroom community and a satellite employment center.

Building and Maintaining Urban Water Infrastructure: Phoenix, Arizona, from 1950 to 2003

Clean urban water, distributed and collected through centralized regional infrastructure, is a driving force in development of the rapidly growing metropolitan regions of the arid Southwest. This study examines the internal magnitude and location of water infrastructure in the city of Phoenix, Arizona, from 1953 to 2003. Regional building-permit data were the basis for identifying six cycles of boom-and-bust real estate activity. Using Water Services Department GIS files, we find that the grid of 1-mile arterial streets provided a systematic framework for incremental water infrastructure expansion. Over this 50-year period, the water system consolidated existing settlements with private water sources and aggressively provided revenue-generating services to an expanding customer base. By 1994–2003, however, new urban fringe development existed only at the northern and southwestern boundaries of this extensive central city. Water infrastructure activities now increasingly included replacement for intensified service, renovation, maintenance, and repair. Detailed analyses of this and other urban water systems provide an additional source of broad insights into processes of both external fringe development and internal land intensification.