Sprawl and Health

Dumbaugh 2005 - "Safe Streets, Livable Streets"

Dumbaugh, Eric
"Safe Streets, Livable Streets"
Journal of the American Planning Association
Summer 2001; vol.71, n.3; pp.283-300
On the Web
Relevance: low

While conventional wisdom recommends limiting roadside hazards, such as trees, and increasing lane and shoulder width will reduce the number and severity of crashes where the driver leaves the roadway, this author posits that trees and narrow lanes encourage drivers to drive more slowly and carefully, reducing the total number of crashes.

The author cites a few studies, including on in Washington on an urban/rural arterial (HWY 99?), where the presence of trees, sign supports, and other fixed objects is associated with fewer total crashes while wider lanes and shoulders are associated with more crashes. The author then conducts his own study comparing different sections of the same roadway, finding similar results.

I'd say that the numerical results in this study are a little squishy, the they and the theory are nonetheless very compelling.

Ewing 2002 - "Measuring Sprawl and Its Impact"

Ewing, Reid; Pendall, Rolf; Chen, Don
"Measuring Sprawl and Its Impact"
Smart Growth America
2002
On the Web
Relevance: high

Ewing et al. created a sprawl index for ~83 metropolitan areas, incorporating density, land use mix, centeredness, and street accessibility. The authors also estimated the impact of sprawl on various transportation-related outcomes. They found that a higher degree of sprawl is associated with higher average vehicle ownership, daily VMT per capita, annual traffic fatality rate, and maximum ozone level; more sprawl was associated with a lower share of work trips by transit and walking. Note that, as with most sprawl studies, we can't assume a causal relationship.

Pucher 2003 - “Promoting Safe Walking and Cycling to Improve Public Health: Lessons from The Netherlands and Germany”

Pucher, John; Dijkstra, Lewis.
“Promoting Safe Walking and Cycling to Improve Public Health: Lessons from The Netherlands and Germany.”
American Journal of Public Health
September 2003; v.93, n.9; pp.1509-1516
On the Web
Relevance: high

Pucher and Dijkstra used data from national travel and crash surveys to compute fatality trends fatality and injury rates for pedestrians and cyclists in The Netherlands, Germany, and the United States.  The authors found that Americans walked/biked far less than do Dutch and Germans but were much more likely to be killed or injured than were Dutch and German pedestrians and cyclists, both on a per-trip and per-kilometer basis.  Causes include urban design and traffic regulations.

Retting 2003 - “A Review of Evidence-Based Traffic Engineering Measures Designed to Reduce Pedestrian-Motor Vehicle Crashes”

Retting, Richard A.; Ferguson, Susan A.; McCartt, Ann T.
“A Review of Evidence-Based Traffic Engineering Measures Designed to Reduce Pedestrian-Motor Vehicle Crashes”
American Journal of Public Health
September 2003; v.93, n.9.; pp. 1456-1463.
On the Web
Relevance: low

The authors reviewed studies on engineering measures used to reduce the risk of pedestrian injuries.  These measures were classified into speed control, separation of pedestrians from vehicles (in time and space), and increased visibility of pedestrians. Highly effective measures include:

• single-lane roundabouts,
• sidewalks,
• exclusive pedestrian signal phasing that stops all traffic while pedestrians cross all ways,
• pedestrian refuge islands, and,
• increased intensity of roadway lighting

Rivara 1989 - “Analysis of Fatal Pedestrian Injuries in King County, WA and Prospects for Prevention”

Rivara FP, Reay DT, Bergman AB.
“Analysis of Fatal Pedestrian Injuries in King County, WA and Prospects for Prevention”
Public Health Reports
May-June 1989; v.104, n.3; pp.293-297.
On the Web
Relevance: medium

The authors analyzed pedestrian fatalities for 12 months in King County, WA.  They found that victims were generally children (29%), the elderly (34%), or intoxicated adults (24%).

Lucy 2003 - “Mortality Risk Associated With Leaving Home: Recognizing the Relevance of the Built Environment”

Lucy, William H.
“Mortality Risk Associated With Leaving Home: Recognizing the Relevance of the Built Environment”
American Journal of Public Health
September 2003; v.93,n.9; pp.1564-1569
On the Web
Relevance: high

In looking traffic fatalities and homicides by stranger in 15 metropolitan areas, Lucy concluded that traffic fatalities pose a real danger to living in low density areas that should be balanced against the expected lower crime risk.  In short, he found that exurban areas were often more dangerous than central cities or inner suburbs, primarily due to the higher risk of traffic fatalities.  Low-density, outer counties had the most traffic fatalities and homicides by stranger while some inner suburban counties were the least dangerous areas overall.

Jacobsen 2003 - “Safety in Numbers: More Walkers and Bicyclists, Safer Walking and Bicycling”

Jacobsen, Peter Lyndon
“Safety in Numbers: More Walkers and Bicyclists, Safer Walking and Bicycling”
Injury Prevention
September 2003; v.9,n.1; pp.205-209.
One the Web
Relevance: high

Jacobsen analyzed various datasets from Europe and California to compare accident rates per capita across differing rates of walking/biking.  He found that as the rates of walking/biking increase, the total number of accidents increases as expected, but the likelihood that an individual pedestrian or cyclist will be hit by a car decreases.

Harruff 1998 - “Analysis of Circumstances and Injuries in 217 Pedestrian Traffic Fatalities”

Harruff RC, Avery A, Alter-Pandya AS.
“Analysis of Circumstances and Injuries in 217 Pedestrian Traffic Fatalities”
Accident Analysis and Prevention
January 1998; v.30,n.1; pp.11-20
On the Web
Relevance: high

Harruff et al analyzed 217 pedestrian fatalities in King County, WA to describe the most common situations and characteristics of pedestrian fatalities.  The average annual pedestrian fatality rate for all pedestrians overstates the risk for responsible, able-bodied adults but understates the risk for vulnerable groups such as the elderly.  Alcohol consumption, disregard of traffic rules, and being male also increase the fatality risk. 

Ewing 2003 - "Urban Sprawl as a Risk Factor in Motor Vehicle Occupant and Pedestrian Fatalities"

Ewing, Reid, PhD; Richard A. Scheiber; Charles v. Zegeer
“Urban Sprawl as a Risk Factor in Motor Vehicle Occupant and Pedestrian Fatalities”
American Journal of Public Health
September 2003; v93, n.9; pp 1541-1545.
On the web
Relevance: High

The authors created a sprawl index for 448 US Counties in the largest 101 metropolitan areas.  For every 1% increase in the index (i.e. more compact, less sprawl), all-mode traffic fatality rates fell by 1.49% and pedestrian fatality rates fell by 1.47% to 3.56%, after adjusting for pedestrian exposure. In short, places that sprawled more had higher death rates from traffic accidents.

In short -- people who live in more sprawling metropolitan counties were more likely to die in car accidents.