Ivan Cheung

Substance Use, Social Networks, and the Geography of Urban Adolescents

This article demonstrates a research strategy and prevention methodology for substance using urban youth that incorporates individual, social, and geographical parameters to systematically understand the ecology of risk and protection for urban youth. The primary goal of this study was to describe and analyze substance using and nonusing urban adolescents’ social networks; risky and protective settings where they socialize; and the relationship to health outcomes such as substance use, depression, and stress. Geographic Information Systems (GIS) derived spatial relationships and analyses between the specific locations where the teens are active, their subjective ratings of these locations, and objective environmental risk data. These social network and GIS data were merged to form a detailed description and analysis of the social ecology of urban adolescent substance use. A case study was constructed to illustrate the methodology of creating a three-dimentional ecological profile that helps explain these relationships and provides preventive applications. Linear distances were computed between the homes of the users and the risky and safe places that they identified. On average, the distance between users’ homes and their identified safe places was three times the distance between their homes and their identified risky places. This study provides support for understanding urban adolescent substance use through the detailed and multiple dimensional analysis of teens’ social ecologies.

Skills in Professional Geography: An Assessment of Workforce Needs and Expectations

This study compares the skills of professional geographers and the needs of employer organizations across major sectors of the U.S. workforce. Following a series of focus groups, two surveys were developed to explore: (1) the extent to which specific skills were performed by geographers in different professional positions, and (2) the value of and anticipated demand for those skills from the perspective of employers. Overall, respondents in the focus groups and both surveys emphasized the need for general skills ranging from time management and writing ability to information management and computer literacy. Employers also cited many geographic skills as being vital for enhancing the work of professionals in all types of organizations. Competency in field methods, the ability to work across disciplinary boundaries, and spatial thinking were three skill areas that characterized the work of geographic professionals irrespective of specialty.

Declines in fatal crashes of older drivers: Changes in crash risk and survivability

OBJECTIVES Previous research has found that older driver fatal crash involvement rates per licensed driver declined substantially in the United States during 1997-2006 and declined much faster than the rate for middle-age drivers. The current study examined whether the larger-than-expected decline for older drivers extended to nonfatal crashes and whether the decline in fatal crash risk reflects lower likelihood of crashing or an improvement in survivability of the crashes that occur. METHODS Trends in the rates of passenger vehicle crash involvements per 100,000 licensed drivers for drivers 70 and older (older drivers) were compared with trends for drivers ages 35-54 (middle-age drivers). Fatal crash information was obtained from the Fatality Analysis Reporting System for years 1997-2008, and nonfatal crash information was obtained from 13 states with good reporting information for years 1997-2005. Analysis of covariance models compared trends in annual crash rates for older drivers relative to rates for middle-age drivers. Differences in crash survivability were measured in terms of the odds of fatality given a crash each year, and the historical trends for older versus middle-age drivers were compared. RESULTS Fatal crash involvement rates declined for older and middle-age drivers during 1997-2008 (1997-2005 for the 13 state subsample), but the decline for drivers 70 and older far exceeded the decline for drivers ages 35-54 (37 versus 23 percent, nationally; 22 versus 1 percent, 13 states). Nonfatal injury crash involvement rates showed similarly larger-than-expected declines for older drivers in the 13 state subsample, but the differences were smaller and not statistically significant (27 percent reduction for older drivers versus 16 percent for middle-age drivers). Property-damage-only crash involvement rates declined for older drivers (10 percent) but increased for middle-age drivers (1 percent). In 1997, older drivers were 3.5 times more likely than middle-age drivers to die in police-reported crashes (6.2 versus 1.8 deaths per 1000 crashes), but this difference was reduced during the 9-year study period to 2.9 times, as the rate of older drivers dying in a crash declined (5.5 deaths per 1000 crashes in 2005) and the death risk remained relatively stable for middle-age drivers. CONCLUSIONS Contrary to expectations based on increased licensure and travel by older drivers, their fatal crash risk has declined during the past decade and has declined at a faster rate than for middle-age drivers. The decreased risk for older drivers appears to extend not only to nonfatal injury crashes but also to property-damage-only crashes, at least as reported to police in the 13 states included in the nonfatal injury analysis. Although insurance collision data suggest that overall crash risk of older drivers may not be changing relative to middle-age drivers, the current analysis indicates that the reduced fatality risk of older drivers reflects both less likelihood of being involved in a police-reported crash and greater likelihood that they will survive when they do crash.

The World Settles in: Washington, DC, as an Immigrant Gateway

This study examines the ethnic geography of a new immigrant gateway, Washington, DC. According to Census 2000, more than 832,000 foreign-born individuals reside in the Washington metropolitan region. This research uses Immigration and Naturalization Service (INS) data in an effort to map the residential decisions of immigrant newcomers by zip code from 1990 to 1998. Spatially, a very diverse, dispersed, and suburbanized pattern of newcomer settlement emerges, a pattern that contradicts many of the assumptions of the spatial assimilation model. Whereas the overall pattern is one of dispersion, an analysis of country-of-origin groups results in a settlement continuum ranging from concentrated (Vietnamese) to highly dispersed (Indians). Current research in Washington suggests that a pattern of heterolocalism (community without propinquity) may be a better model for understanding the role of immigrant settlement patterns and networks.

Traffic speeds associated with implementation of 80 mph speed limits on West Texas rural interstates

PROBLEM In 2006 Texas raised the daytime speed limit for passenger vehicles on segments of I-10 and I-20 from 75 to 80 mph. METHODS Traffic speeds were measured before and 3, 12, and 16 months after the limit was changed. RESULTS During the 16-month period following the speed limit increase, mean speeds of passenger vehicles on I-20 increased by 9 mph relative to the comparison road, where no speed limit change occurred and traffic speeds declined. On I-10 mean speeds increased by 4 mph relative to the comparison road. Limiting the analysis to the month before the speed limit change and 1 year later, the proportion of drivers exceeding 80 mph was 18 times higher on I-20 and 2 times higher on I-10. DISCUSSION The smaller speed increases on I-10 may be related to its proximity to the U.S. border with Mexico. Highly visible border patrol activity coincided with posting of the higher speed limit. Long-term monitoring in other states suggests that traffic speeds in Texas are likely to continue to increase. IMPACT ON INDUSTRY The present study adds to the wealth of evidence that increased speed limits lead to increased travel speeds. The primary countermeasures to reduce the risk of speed-related crashes include highly visible police traffic enforcement and the use of speed cameras accompanied by publicity.

Adolescent Substance Use and Abuse Prevention and Treatment: Primary Care Strategies Involving Social Networks and the Geography of Risk and Protection

The use and abuse of licit and illicit substances in adolescence is a national public health concern. This behavior impairs healthy development for many adolescents in the United States. Although not every adolescent who becomes a regular user of licit and illicit substances will develop a substance abuse disorder, all adolescents using these substances can experience a life-threatening outcome. Understanding the epidemiology and social profile of adolescent substance use, namely the risk and protective factors and the environmental and genetic factors, is essential to the development of strategies for prevention. There are many methods that can be employed to better assess environments in which adolescents live. The method discussed in this paper is descriptive and utilizes Geographic Information Systems (GIS) technology. The primary goal of this paper is to illustrate and describe an analysis of substance using and non-substance using adolescents, their social networks, the risky and protective settings where they socialize, and the relationship of these variables to health outcomes such as substance use, depression, and stress. Published data from the researchers’ recent investigation examine the effect of social network affiliations and geographical risk factors on drug involvement and illustrate how these factors may then be incorporated into prevention and intervention planning, especially in medical settings.