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InTransition Magazine : Transportation Planning, Practice & Progress

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Research Exchange

About Research Exchange

  • Research Exchange gathers brief summaries of ongoing or recently completed research about critical topics in transportation. We invite readers to suggest studies that merit inclusion.

A Grocery Injustice: Urban Flight of Supermarkets Charted

Canadian researchers used GIS technologies to map the historical evolution of so-called “food deserts” in the city of London, Ontario, from 1961 to 2005. They found that like many North American cities in the 20th century, London’s supermarkets tended to migrate from the city core to the suburbs. Residents who remained in the poorer neighborhoods were left without adequate access to quality, affordable foods.

In the 1800s and early 1900s, groceries were most plentiful in the cities, where small, independently owned markets were integral parts of neighborhoods. That all changed with the rise of the automobile. Retailers began organizing into chains that maximized their profits, and the size of stores’ floor space and inventories exploded. The footprint of a typical grocery store in the Ontario city (population 350,000) grew from 850 square meters (roughly 9,150 square feet) to about 4,000 square meters (43,000 square feet) today, the study noted. This trend toward supermarkets and superstores led franchises to build their new stores in the suburbs, where the customers were wealthier and vacant properties, parking space and road access were in good supply.

Meanwhile, food deserts—described as “socially distressed neighborhoods with relatively low average household incomes and poor access to healthy food”—emerged in London. The remaining city supermarkets became harder to reach for pedestrians, forcing residents to buy identical groceries at prices 1.6 times higher at small food shops and convenience stores, according to the study. By mapping London’s public transit routes, the researchers found that buses ran close enough to the supermarkets to help most city residents, with the notable exception of the “highly distressed” neighborhood of East London.

The study’s authors warned that the presence of food deserts was a problem with the potential to erode a city’s vitality. “Ultimately, the closure of the supermarkets will result in an increased unemployment rate in distressed cores, fewer visitors to surrounding retailers, and potential impacts to the health and well-being of already vulnerable populations.” To fight the trend, they suggested cities provide financial incentives like tax breaks or building restoration initiatives to attract new stores. Cities can also change their zoning or parking regulations to make it easier for stores to move into areas that need them.

“Mapping the Evolution of ‘Food Deserts’ in a Canadian City: Supermarket Accessibility in London, Ontario, 1961-2005” was published in the International Journal of Health Geographics in April.

—Researchers: Kristian Larsen and Jason Gilliland, University of Western Ontario.

Heaven on Wheels: Churches Willing to Transport Disabled

For disabled residents in transit-starved areas, faith-based organizations (FBO) could be a godsend. A survey of nearly 300 FBOs in rural areas found that many are ready, willing and able to assist.

Of the 25 percent of Americans living in rural areas, 41 percent have no public transportation services in their counties. About 95 percent of federal transportation subsidies go to the 75 percent of people living in cities, while the remaining 5 percent of the funds go to rural areas. Researchers from the University of Montana attempted to gauge the potential of the 120,000 U.S. churches located in non-metropolitan counties to offer transportation services for people with disabilities.

They found that while many were noncommittal about providing such services, 32 percent said they were willing or very willing to do so. About one-third of respondents claimed their faith community owned at least one vehicle, and about 18.5 percent of those were equipped with a lift or ramp for wheelchairs or other mobility devices.

Of the potential barriers that could block the FBOs’ participation, wariness of government entanglement did not appear to be an overwhelming concern. Respondents cited a lack of financial resources, lack of staff to handle the duties, a lack of knowledge about disability-related transportation issues and concerns about time constraints as reasons they might not participate. As far as requirements for their involvement, funding was listed by 74 percent of respondents; 51 percent required their council’s approval; 35 percent wanted some guarantee of freedom of government interference in their church; and about 23 percent indicated they would only participate if it was part of an interdenominational effort.

The authors found the results encouraging, noting, “FBOs are an important element in nearly every rural community. Given that many people in rural communities are in desperate need of transportation ... it is only natural that rural residents turn to those who may feel a religious duty to serve their fellows.”

“Faith-Based Organizations: A Potential Partner in Rural Transportation” appeared in the Journal of Public Transportation Volume 11, No 1, 2008.

—Researchers: Tom Seekins, Steve Bridges, Annesa Santa, Daniel Denis and Andrea Hartsell, University of Montana.

Don’t Vote & Drive

The odds of getting killed driving on Election Day are higher than New Year’s Eve or Super Bowl Sunday. A study of U.S. presidential election days from Jimmy Carter in 1976 to George W. Bush in 2004 found an across the board rise in fatal crashes during polling hours. The researchers compared the same hours on Tuesdays immediately before and after the election days, and found fatality rates were 18 percent higher.

A pair of researchers hypothesized that the combination of the country’s reliance on auto travel and the mobilization of about 55 percent of the population to vote might lead to a rise in fatal motor vehicle crashes. Their investigation concluded that presidential election days averaged 24 fatalities and 800 serious injuries more than normal. The risk was reportedly bi-partisan, as crashes spiked regardless of whether a Democrat or a Republican was elected.

The study mentioned speed, distance, distraction, emotions, confusion over how to get to the polling station and unfit drivers taking to the roads as possible explanations. Lead researcher Donald Redelmeier, of Sunnybrook Health Science Centre, Canada, said that rushing could play a part. “I think it’s more of a reflection of speeding to the polls, or away from the polls, or trying to jam one more thing into an already busy day,” said Redelmeier, also a professor of medicine at the University of Toronto.

The researchers suggest that election organizers stress the importance of safety when encouraging people to get out and vote. Other interventions worth considering might include subsidized public transportation, setting up polling places within walking distances, remote voting or stronger traffic enforcement on election days.

The full study, “Driving Fatalities on U.S. Presidential Election Days,” was published in the Oct. 1 issue of the Journal of the American Medical Association.

—Researchers: Donald Redelmeier, Sunnybrook Health Sciences Centre, Ontario; Robert Tibshirani, Stanford University.

Later Last Call Caused No Change in Crash Injuries

Changing last call caused no lasting change in Ontario’s vehicle crash injury rates. A group of researchers analyzed hospital records in the Canadian province for the four years before and three years after a 1996 law that extended the hour bars could sell alcohol from 1 a.m. to 2 a.m. They found there was no dramatic difference in the rate of motor vehicle collision (MVC) injuries from 2 a.m. to 3 a.m., but a rise was seen in non-MVC injuries.

The study tested two competing schools of thought on what would happen if the last call hour was changed. The “availability theory” predicted the extra hour would lead to higher alcohol consumption and an overall increase in injuries. The “power drinking hypotheses” contended that closing earlier encouraged “loading up” at last call, so it would be safer to spread alcohol sales over a longer period, giving patrons time to finish up and leave at their leisure. The lawmakers in Ontario subscribed to the latter view. The decision to extend the area’s drinking hours was largely intended to minimize the disruptions caused by crowds making an exodus at closing time and binge drinking at last call, according to the study.

The statistics showed a 19 percent decrease in the number of MVC injuries from 11 p.m. to midnight and a smaller decrease for the 1-2 a.m. hour, but no significant change in any other one hour timeframe between 11 p.m. and 3 a.m. The authors noted that road safety initiatives, like a new license suspension law and a graduated licensing law, may have already been fueling a downward trend in drunk driving that partially accounted for the results. While the decreased MVC statistics would seem to support the power drinking theory, the increase in non-MVC injuries appeared to support the availability theory, the authors noted. Several recent studies on small changes in alcohol availability found results similar to those in Ontario, according to the authors.

“Impact of Extended Drinking Hours in Ontario on Motor Vehicle Collision and Non-Motor Vehicle Collision Injuries” was published in the Journal of Studies on Alcohol and Drugs in November 2007.

—Researchers: Evelyn Vingilis, A. Ian McLeod, Gina Stoduto, Jane Seeley and Robert Mann, University of Western Ontario.

The BRT Identity Crisis

Bus rapid transit (BRT) suffers from public perception problems that can be dispelled by building up each system’s own unique identity, according to a recent study. While often faster and more comfortable, BRT has had a tough time shaking some of the negative stereotypes of traditional buses. An evaluation of 22 BRT services currently in operation or under development brought to light a number of common approaches the authors said can serve as models for transit providers.

The study outlined many of BRT’s positive qualities, among them: it has exclusive rights-of-way and offers direct service; it operates like a light rail system but at a reduced infrastructural cost; routes are easier to extend and adapt than rail; it frequently utilizes new technologies; and its affordability to riders. Still, to some, the “bus” in BRT conjures up images of a noisy, polluting, slow and inconvenient vehicle, the study said. Transit providers must fight those perceptions by stressing BRT systems as speedy, quiet and environmentally friendly.

To accomplish this, the authors stressed a few ways that agencies can help build up positive BRT identities. Vehicles can be decorated using a distinct color palette that separates the BRT line as a signature service that is unique from the agency’s standard vehicles. The systems should be given a distinctive name and logo that stresses positive attributes, like its convenience and speed vs. cars or other buses. Clean, aesthetically pleasing visual identifiers should be used to make the line easy to recognize and follow for both locals and tourists, such as common signs/symbols at BRT stops and information kiosks. The authors also suggest that the service be integrated with long-term marketing and advertising plans.

“Bus Rapid Transit Identity: An Overview of Current ‘Branding’ Practice” appeared in the Journal of Public Transportation Vol. 11, No. 2, 2008.

—Researchers: Daniel Baldwin Hess, University at Buffalo; Alex Bitterman, Rochester Institute of Technology.

Zig-Zag Crosswalk Deemed Safe, Efficient for Roundabouts

Alternative crosswalk setups and signal systems have the potential to significantly reduce traffic backups in roundabouts, according to a study on how to improve the crossings for vision-impaired pedestrians.

Because of their safety benefits and low maintenance costs, roundabouts are becoming more common in the U.S., and that popularity has raised questions about their pedestrian accessibility, particularly for the blind. The researchers noted that a database of over 1,000 American roundabouts listed only two (both in Florida) with pedestrian signals. Since that will likely change in the future, the researchers aimed to evaluate which pedestrian crossing setups would cause the least disruptions to traffic.

The traffic impacts of two signal systems and three crossing positions were simulated based on traffic volumes at real roundabouts. The researchers concluded that a conventional green-yellow-red traffic signal was far inferior to a high-intensity activated crosswalk (HAWK) system, which breaks the pedestrian crossing up into two stages. The HAWK features a flashing red light sequence that allows motorists to drive through with caution if they see that a pedestrian has safely crossed their side of the street.

Two crosswalk configurations were deemed better than the most obvious one, a straight crosswalk near the mouth of the roundabout. One was the “distal crossing,” a straight crosswalk located a few car lengths before the roundabout. The most effective configuration was a zig-zag crossing that forces pedestrians to cross near the mouth of the roundabout, walk several feet down a median, then cross the second half of the road. The zig-zag walk allowed more vehicles to fit in the roundabout. It also split the traffic disruption into two phases, reportedly reducing delays by up to 70 percent over the first configuration.

The study, “Toward Roundabout Accessibility—Exploring the Operational Impact of Pedestrian Signalization Options at Modern Roundabouts,” appeared in the Journal of Transportation Engineering in June.

—Researchers: Bastian Schroeder, Nagui Rouphail and Ronald Hughes, North Carolina State University.

Inexperienced Drivers Expect the Unexpected

An Israeli study found veteran drivers identified road signs better than inexperienced drivers when they were placed at typical locations, but fared far worse than inexperienced drivers when the signs were at uncommon spots. The researchers reasoned that over time, drivers’ expectation for seeing signs in familiar positions becomes so hardened that straying from these expectations can be hazardous.

Twenty drivers (average age 18.45) with a maximum of six months on the road and 20 more (average age 26.8) with at least five years experience were paid to take part in the study. The participants were shown 160 photos of traffic scenes -- 152 decoys and eight target pictures. The target photos showed “no left turn” (NLT) or “no right turn” (NRT) signs in their correct (on the right-hand side of the road) and incorrect (on the left) positions. The photos were followed by a question on the screen concerning the presence or absence of an object (such as, was there a no left turn sign in the last picture?). Participants answered by pressing a yes or no button. Their response times were recorded.

The groups produced dramatically different results. The experienced drivers were likely to identify the NRT and NLT signs when they were on the right side 94 and 88 percent of the time, respectively. When the signs were on the left curb, the group detected each of them only 53 percent of the time. Inexperienced drivers noticed the NLT signs on both sides of the road an equal 82 percent of the time. They saw the NRT sign on the left—supposedly the incorrect side—at an even higher rate than the right side, 82 to 67 percent. “This is because the inexperienced drivers are insensitive to the ‘appropriateness’ of the location of signs,” the authors noted.

“When signs are misplaced, crashes can be caused by inappropriate placement rather than inappropriate driving. Highway designers should ensure that their design conforms to standards that shape experienced drivers’ expectations,” the report recommends.

“The Relation Between Driving Experience and Recognition of Road Signs Relative to Their Locations” was published in Human Factors in April.

—Researchers: Avinoam Borowsky, David Shinar and Yisrael Parmet, Ben Gurion University of the Negev, Israel.

Doctors: Sprawl Hazardous to Teen Drivers’ Health

Urban sprawl poses a particular risk for teen drivers, according to research conducted by a pair of doctors. Since teen driver fatality rates are four to eight times higher than adults, land use patterns which increase the miles driven daily by teens therefore increase their risk of being killed in a crash, according to the study.

The researchers gathered demographic data from the 2001 National Household Transportation Survey and developed an algorithm to measure sprawl, daily miles driven by teens, demographic characteristics and the probability of teens driving more than 20 miles each day in counties with varying levels of sprawl. Of the 4,528 teens (ages 16-19) surveyed, 48 percent reported that they didn’t drive, 27 percent drove less than 20 miles daily and 25 percent drove greater than 20 miles.

Teens in sprawling counties were reportedly more than twice as likely to drive over 20 miles per day than teens living in more compact areas. This association was stronger among the youngest and least experienced drivers. The odds of boys ages 16 and 17 driving more than 20 miles per day was 9 percent in compact counties and 24 percent in sprawling ones. The average distance driven by the teens was 15.6 miles per day.

“Certain teenage characteristics, like the tendency to take risks, are not going to change. This makes health behavior modification in this age group very difficult. However, our results suggest that changing the way we develop and use land in order to minimize our dependence on our vehicles could be an effective method of reducing the risk of serious injury or death among teen drivers in the United States,” said Dr. Matthew Trowbridge, the study’s lead researcher.

“Urban Sprawl and Miles Driven Daily by Teenagers in the United States” appeared in the American Journal of Preventive Medicine in March 2008.

—Researchers: Matthew Trowbridge, University of Virginia; Noreen McDonald, University of North Carolina at Chapel Hill.

Job Stresses Puff Up Smoking Rates Among Transit Workers

Transit operators may be more likely to light up to lighten up from stressful times on the job. A study of San Francisco Municipal Railway (Muni) operators found that the frequency of work hassles was significantly associated with the likelihood of smoking increases, starting smoking or maintaining their habit over a 10-year period.

The study examined 654 Muni workers who participated in a pair of health studies and medical examinations conducted in 1983-85, and then a decade later in 1993-95. Workers were asked about the frequency of their smoking habits in their exams. A questionnaire asked them to rate how often they dealt with a long list of typical job problems over the last year, such as equipment malfunctions, passengers causing problems, overcrowding, long hours, accidents, traffic and others. The survey also included questions intended to measure the workers’ emotional burnout and how long it takes for them to unwind after work.

The study found that after 10 years, 35 percent of the operators had increased, initiated or maintained their smoking levels, a percentage that was well higher than that of California residents from comparable age groups, the authors noted. Of these 230 workers, about 10 percent increased their smoking, 17 percent started smoking and 72 percent maintained their habits. These rates were found to be higher among Muni’s black and female operators. While burnout and time to unwind did not appear to be significantly associated with the likelihood of smoking over time, the frequency of job problems did, according to the study.

A number of studies have shown that workers in blue collar and service occupations tend to smoke at rates well higher than people in white collar and professional occupations. The authors suggested that transit organizations consider smoking cessation programs or other measures aimed at reducing job stress as a way to lower smoking.

“Occupational Correlates of Smoking Among Urban Transit Operators: A Prospective Study” appeared in Substance Abuse Treatment, Prevention, and Policy in December 2007.

—Researchers: Carol Cunradi, Rob Lipton and Aniruddha Banerjee, The Prevention Research Center (PRC) of the Pacific Institute for Research and Evaluation, Berkeley, Cal.

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