Archives 1 - Traffic Congestion and Transportation Trends
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- The purpose of this study is to estimate the costs of motor vehicle-related fatal and nonfatal injuries in the United States in terms of medical care and lost productivity by road user type.
- Results report that motor vehicle-related fatal and nonfatal injury costs exceeded $99 billion.
- Costs associated with motor vehicle occupant fatal and nonfatal injuries accounted for 71 percent ($70 billion) of all motor vehicle-related costs, followed by costs associated with motorcyclists ($12 billion), pedestrians ($10 billion), and pedalcyclists ($5 billion).
- The substantial economic and societal costs associated with these injuries and deaths reinforce the need to implement evidence-based, cost-effective strategies.
- Evidence-based strategies that target increasing seat belt use, increasing child safety seat use, increasing motorcyclist and pedalcyclist helmet use, and decreasing alcohol-impaired driving are available.
Naumann, Rebecca B., Dellginer, Ann M., Zaloshnja, Eduard, Kawrence, Bruce A. and Miller, Ted B. “Incidence and Total Lifetime Costs of Motor Vehicle-Related Fatal and Nonfatal Injury by Road User Type, United States, 2005.” Traffic Injury Prevention. 11.4 (2010): 353-360.
- This study explores how school policies influence the environmental impacts of school commutes, motivated by increased interest in school choice policies and in reducing bus services to address recent budget shortfalls.
- Results indicate that eliminating district-wide school choice (i.e., returning to a system with neighborhood schools only) would have significant impacts on transport modes and emissions, whereas in many cases proposed shifts in school choice and bus-provision policies would have only modest impacts.
- Policies such as school choice and school siting may conflict with the goal of increasing rates of active (i.e., nonmotorized) school commuting.
- Researchers report that these findings underscore the need to critically evaluate transportation-related environmental and health impacts of currently proposed changes in school policy.
Marshall, JD, Wilson, RD, Meyer, KL, Rajangam, SK, McDonald, NC, and Wilson, EJ. “Vehicle Emissions during Children’s School Commuting: Impacts of Education Policy.” Environmental Science and Technology. (2010)
- This research brief presents an overview of findings demonstrating the potential impact of infrastructure investments and other transportation programs on walking and bicycling for transportation, and on related health outcomes.
- It also focuses on public transit, greenways and trails, school-related infrastructure and programs, pedestrian and bicycle facilities, and efforts to manage car traffic.
Rodriquez, DA. “Research Brief: Active Transportation, Making the link from Transportation to Physical Activity and Obesity.” Active Living Research. (2009): available at http://www.activelivingresearch.org/files/ALR_Brief_ActiveTransportation.pdf
- This study investigates the characteristics of student travel behaviors before the implementation of SRTS program and identifies the influential factors affecting the number of children to walk or bike to school.
- Parents reported the following as the five primary factors affecting children’s walking or biking:
- distance (67.0%)
- traffic speed along route (53.7%)
- traffic amount along route (51.3%)
- violence or crime (42.1%)
- intersection safety (38.2%)
- Parents reported the following as the five primary factors that would change their decisions and allow their children to walk or bike to school:
- distance (25.5%)
- safety of intersections and crossings (22.0%)
- weather or climate (21.9%)
- presence of an adult cowalker (17.5%)
- convenience of driving (15.0%)
- Researchers suggest that distance between the rankings reveal a variance between people’s perceptions and reactions.
- Subjective opinions were also considered in this study demonstrating that most students and parents held positive attitudes toward students walking or biking to school:
- Forty percent of students consider walking or biking to school “fun” or “very fun” and less than 10 percent of students consider it “boring or “very boring”.
- 57.2 percent of students consider it “healthy” or “very healthy” to walk or bike to school.
- 78.8 percent of students have asked for permission to walk or bike to school.
- Only 4.1 percent of students believed their schools discourage or strongly discourage students to walk or bike to school.
- 32.9 percent of parents will allow their children to walk or bike alone at different grades.
Zhou, Huaguo, Zhao, Jiguang, Hsu, Peter, and Rouse, Jeanette. “Identifying Factors Affecting the Number of Students Walking or Biking to School.” Institute of Transportation Engineers Journal. 79.10 (2009).
- This study analyzes data from a sample of 4,156 metropolitan Atlanta residents who were interviewed by telephone and kept two-day travel diaries.
- 10.9% of the sample reported walking for transportation, 2.6% did enough to meet the recommended 30 minutes per day.
- Participants who took more trips by any mode are more likely to do some walking, additional trips by transit were significantly associated with greater odds of walking.
- On average, transit users walked 1.72 km per day, but those who did not use transit walked only 0.16 km per day.
- This study implies that use of transit increases distance walked per day.
Lachapelle, Ugo and Frank, Lawrence D. “Transit and Health: Mode of Transport, Employer-Sponsored Public Transit Pass Programs, and Physical Activity.” Journal of Public Health Policy. 30 (2009): S73-S94.
- This study analyzes rates of walking and biking to school among low-income and minority youth in the United States.
- Hispanics have the highest rate of active transportation (27.7%) while whites have the lowest (9.4%).
- Results demonstrate that families earning less than $20,000 walk more than twice as much as students from households earning more than $60,000.
- High school students have the lowest rates of active transport across all income and racial groups.
- Living within a half-mile of school greatly increases the likely of walking or biking to school.
- A significant implication of these findings is that Safe Routes to School programs have the potential to benefit minority and low-income students, especially because many of those students are more likely to live near the school they attend.
McDonald, Noreen C. “Critical Factors for Active Transportation to School Among Low-Income and Minority Students. Evidence from the 2001 National Household Travel Survey.” American Journal of Preventive Medicine. 34.4 (2008): 341-344.
- This study reviews survey results among university employees. Survey results reveal that car commuters find their journey more stressful than other mode users.
- Walking and cycling journeys are found to be the most relaxing and exciting form of travel.
- Researchers suggest that implications of this study include sustainable transport policy initiatives to persuade people to use their car less.
Gatersleben, Birgitta and Uzzell, David. “Affective Appraisals of the Daily Commute. Comparing Perceptions of Drivers, Cyclists, Walkers, and Users of Public Transport.” Environment and Behavior. 39.3 (2007): 416-431.
- In 1969, 40.7% of students walked or biked to school, by 2001 only 12.9% of children walked or biked to school.
- This study documents the sharp decrease in Active Transportation to School (ATS) from 1960 to 2001 as well as an increase distance to school. A decrease in walking represents an important loss of everyday physical activity for students.
- This article suggests that policies affecting this distance, such as school siting, should begin to explicitly consider access to schools in planning decisions. Public officials should also continue to support programs such as Safe Routes to School that address safety concerns.
McDonald, Noreen C. “Active Transport to School: Trends Among U.S. Schoolchildren 1969-2001.” American Journal of Preventive Medicine. 32.6 (2007): 509-516.
- The purpose of this report is to evaluate the effectiveness of the SRTS program in reducing crashes, injuries and fatalities involving children in the vicinity of the projects, the impact of the program on levels of walking and bicycling to school, and the safety benefits of the program in comparison with other highway safety programs.
- Evaluation results report an increase in walking and bicycling to and from school from 10%-200% depending on the source of information (direct observation vs. parent estimates).
- California reports an overall decline in the number of child pedestrians/bicyclists injured in Safe Routes to School program areas.
- SRTS projects saw a similar decline in the actual numbers of child pedestrian/bicyclist injuries as the control areas and across California. However, when factoring in the increase in walking and bicycling in the SRTS projects and increased exposure to risk, the SRTS program showed a decreased rate of injuries and a net benefit in terms of safety for affected students. The magnitude of the safety benefit ranged from 0 to 49% depending on the increase in the walking/bicycling rate.
- Cost-benefit comparisons performed by Caltrans resulted in a cost per collision reduction ranging between $40,397 and $282,779.
- Improvements in traffic congestion and air quality near school are also considered beneficial but difficult to include in a cost-benefit evaluation.
Orenstein, Marla R., Gutierrez, Nicole, Rice, Thomas M., Cooper, Jill F. and Ragland, David R. "Safe Routes to School Safety and Mobility Analysis.” UC Berkeley Traffic Safety Center. (April 1, 2007). Paper UCB-TSC-RR-2007-1.
- This study investigates whether an aggressive traffic violation enforcement program could reduce motor vehicle crashes (MVCs), injury collisions, fatalities, and fatalities related to speed, and decrease injury severity in crash victims treated at the trauma center.
- A vigorous enforcement program was established in Fresno, California. Data on citations, collisions, fatal collisions, and fatalities related to speed, as well as injury severity from the trauma registry, were collected for the year before program onset (2002), during the first year (2003), and after full implementation (2004).
- Results report a significant increase in citations issued, with marked decreases in motor vehicle crashes, injury collisions, fatalities, and fatalities related to speed.
- This study implies that traffic enforcement is a simple and easily implemented injury prevention program with immediate benefit.
Davis, James W., Bennink, Lynn D., Pepper, David R., Parks, Steven N., Lemaster, Deborah M., and Townsend, Richard N. “Aggressive Traffic Enforcement: A Simple and Effective Injury Prevention Program.” The Journal of Trauma, Injury, Infection, and Critical Care. 60.5 (2006): 972-977.
- This article examines single-use, low-density land use patterns and reports that a 5% increase in neighborhood walkability is associated with:
- 32.1% more minutes devoted to physically active travel
- About one-quarter point lower BMI (0.228)
- 6.5% fewer vehicle miles traveled (VMT) per capita
- 5.6% fewer grams of Nitrogen Dioxide per capita
- 5.5% fewer grams of volatile organic compound (VOC) emitted per capita
Frank, Lawrence D., Sallis, James F., Conway, Terry L., Chapman, James E., Saelens, Brian E. and Bachman, William. “Many Pathways from Land Use to Health. Associations between Neighborhood Walkability and Active Transportation, Body Mass Index, and Air Quality.” Journal of the American Planning Association. 72.1 (2006): 75-87.
- This article focuses on the relationship between the built environment, travel behavior, and public health outcomes.
Frank, Lawrence D. and Engelke, Peter. “Multiple Impacts of the Built Environment on Public Health: Walkable Places and the Exposure to Air Pollution.” International Regional Science Review. 28(2) (2005): 193-216.
- This study examines the association between traffic-related pollution and childhood asthma among 208 children in 10 communities in Southern California.
- Results demonstrate an association between increased asthma and closer residential distance to a freeway, indicating that respiratory health in children is adversely affected by local exposures to outdoor Nitrogen Dioxide or other freeway-related pollutants.
- The implications of these data are important and relevant because they strengthen emerging evidence that air pollution can cause asthma and that traffic-related pollutants are partly responsible for this association.
Gauderman, James W., Avol, Edward, Lurmann, Fretd, Kuenzli, Nino, Gilliland, Frank, Peters, John and McConnell, Rob. “Childhood Asthma and Exposure to Traffic and Nitrogen Dioxide.” Epidemiology. 16.6 (2005): 737-743.
- This study examines trends in walking among U.S. adults and youth for a Healthy People 2010 objective that calls for increased walking of trips 1 mile or less (25% increase for adults and 50% increase for youth).
- By tracking and analyzing national transportation surveys, results demonstrate adults reported more walking in 2001 (21.2%) than in 1995 (16.6%).
- In 2001, only about one third (35.9%) of children aged 5 to 15 traveled 1 mile or less to school, and of these, 36% traveled by walking. This study reports that trips in 1995 only 31.3% of these children walked to school.
- Despite increases in walking trends, adults and youth still do not meet objectives for Healthy People 2010.
Ham, Sandra A., Macera, Caroline, A. and Lindley, Corina. “Trends in Walking for Transportation in the United States, 1995 and 2001.” Preventing Chronic Disease. 2.4 (2005): 1-10.
- This review of the success of the Safe Routes to School program in Marin County reports an increase in walking and biking to school.
- Student transportation surveys reported a 64% increase in the number of children walking to school, 114% increase in the number of students biking, and 91% increase in the number of students carpooling.
Staunton, Catherine E., Hubsmith, Deborah and Kallins, Wendi. “Promoting Safe Walking and Biking to School: The Marin County Success Story”. American Journal of Public Health. 93.9 (2003): 1431-1434.
- This review uses the Transportation Research Information Services database to identify studies on engineering to reduce speed, separate pedestrians from vehicles, and increase visibility of pedestrians.
- Single-lane roundabouts, sidewalks, exclusive pedestrian signal phasing, pedestrian refuge islands, and increased intensity of roadway lighting yield the most effective increase in pedestrian safety.
- Results report that modifications of the built environment can substantially reduce the risk of pedestrian-vehicle crashes.
- More research is needed in the field of traffic engineering measures and effects on pedestrian safety.
Retting, Richard A., Ferguson, Susan A., and McCartt, Anne T. “A Review of Evidence-Based Traffic Engineering Measures Designed to Reduce Pedestrian-Motor Vehicle Crashes.” American Journal of Public Health. 93.9 (2003):1456-1463.
- This study aims to estimate the likely effect of reduced travel speeds on the incidence of pedestrian fatalities in Adelaide, Australia.
- A scenario in which the speed was reduced from 60 to 50 km/hr suggests a 32% reduction in fatalities and 10% of fatal accidents being avoided altogether.
- The results of the study predict that a small reduction in traveling speed is likely to result in large reductions of impact speed in pedestrian collisions, often to the extent of collision prevention.
Anderson, R., McLean, A., Farmer, M., Lee, B., and Brooks, C. “Vehicle Travel Speeds and the Incidence of Fatal Pedestrian Crashes.” Accident Analysis and Prevention. 29.5 (1997): 667-674.
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