Monday, May 16, 2011

Pedestrian Research Rundown

Hmm, perhaps that wasn't the best choice of titles for a pedestrian blog. At any rate, here's a summary of some of the latest in pedestrian research, for the academically (or not-so-academically) inclined:

Cost-Driven Injury Prevention: Creating an Innovative Plan to Save Lives With Limited Resources
Pedestrian injury costs $20 billion annually. Countermeasures such as blinking crosswalks can be expensive, but expectedly vital to injury prevention efforts. In this study, the researchers aimed to create a new framework of cost-driven surveillance using a detailed analysis of hospital costs and their relationship to location of pedestrian injury. Targeting identified “high cost areas” with effective countermeasures could save lives and be most cost-effective.

The researchers conducted an analysis of billing records of 694 auto versus pedestrian victims treated in San Francisco in 2004. Ninety percent of victims resided in San Francisco, and of 11 city districts, three districts accounted for almost 50% of the total cost.The total cost of injury was $9.8 million, 76 percent of which was publicly funded. Thirty-one percent of victims were admitted, and cost of their care accounted for 76% of the total cost.

Conclusions: These findings provide a roadmap to target costly hot spots for preventive countermeasures. In a climate of limited resources, this kind of roadmap highlights the areas that could most benefit from countermeasures from both an injury prevention and cost-containment standpoint. Cost-driven surveillance is useful in city strategic planning for cost-effective and life-saving pedestrian injury prevention.

Evaluation of Lane Reduction "Road Diet" Measures on Crashes
While potential crash-related benefits are cited by road diet advocates, there has been limited research concerning such benefits. This brief from the the FHWA summarizes a recent reanalysis of studies in Washington, California, and Iowa to compile crash data and gain a better understanding of the impact that road diets can have on crash rates.

The Iowa data indicate a 47 percent reduction in total crashes while the HSIS (California and Washington) data indicate a 19 percent decrease—a substantial difference. These reanalysis results also differ from the original Iowa study results (a 25 percent reduction) and from the original HSIS results (a 6 percent reduction). Combining both data sets results in a 29 percent reduction in total crashes.

Differences in reductions may be a function of traffic volumes and characteristics of the urban environments where the road diets were implemented. The sites in Iowa ranged in AADT from 3,718 to 13,908 and were predominately on U.S. or State routes passing through small urban towns with an average population of 17,000. The sites in Washington and California ranged in AADT from 6,194 to 26,376 and were predominately on corridors in suburban environments that surrounded larger cities with an average population of 269,000.

The authors speculated that while there could have been significant differences in speeds between the rural U.S. or State highway approaching a small town and the road diet section, this calming effect would be less likely in the larger cities, where the approaching speed limits (and traffic speeds) might have been lower before treatment.

Puffin Pedestrian Crossing Accident Study
Puffin facilities are pedestrian-activated crossings that also automatically detect pedestrians in the roadway, and adjust signal timing accordingly. Research has shown that compared to existing pedestrian signal facilities, Puffin facilities can reduce both driver and pedestrian delay at junctions, and improve pedestrian comfort (particularly for older pedestrians and those with impaired mobility). Previous research has also indicated safety benefits. The aim of this study was to quantify the safety benefit.

Crash data was analysed from 50 sites (40 mid-block crossings and ten junctions) that had been converted to Puffin facilities from Pelican (traditional pedestrian-activated) crossings and farside pedestrian signals at junctions. The sites had no other significant changes in layout or operation, and were in general conformance with current Puffin guidance. “Before” and “after” conversion accident data was paired together for each site, negating any biases for particular site factors.

Mid-block Puffin crossings were shown to be safer than Pelican crossings with a mean reduction in personal injury accident frequency of 17%, statistically significant at the 5% level. The accident frequency reduction for the combined sample including junctions was 19%, statistically significant at the 5% level.

Distracted Driving: So What's the Big Picture
In the past five years distracted driving has garnered growing media attention and rapidly emerged as one of the most high-profile, talked-about issues in road safety today.

A major reason for the fractionated efforts to address the issue is that the big picture is often neglected. Like most road safety issues, distracted driving is transdisciplinary in nature and therefore complex both to understand and to solve. Indeed, solutions to mitigate distracted driving have not been well-evaluated so our knowledge of what works is severely limited.

To put the issue into proper perspective, this article from the Treaffic Injury Research Foundation shares insight into many different facets of distracted driving that draws upon existing research, policy documents, and activities in North America.

Mobile Phone Use: A Growing Problem of Distracted Driving
Driver distraction is an important risk factor for road traffic injuries. This report from the World Health Organization focuses on the use of mobile phones while driving, in response to concern among policy-makers that this potential risk to road safety is increasing rapidly as a result of the exponential growth in the use of mobile phones more generally in society. It aims to raise awareness about the risks of distracted driving associated with mobile phone use, and to present countermeasures that are being used around the world to tackle this growing problem.

Some interesting tidbits from the report:

1. The proportion of drivers using mobile phones while driving has increased over the past 5–10 years, ranging from 1% to up to 11%.

2. There is a growing body of evidence that shows that the distraction caused by mobile phones can impair performance in a number of ways, e.g. longer reaction times (notably braking reaction time, but also reaction to traffic signals), impaired ability to keep in the correct lane, shorter following distances, and an overall reduction in awareness of the driving situation.

3. Studies suggest that drivers using a mobile phone are approximately four times more likely to be involved in a crash. This increased risk appears to be similar for both hand-held and hands-free phones.


  1. Nice roundup! That's some interesting stuff.

  2. Very nice. Thank you for gathering these. This will be one of those blog posts that will need to be bookmarked.

  3. Thanks! I thought the research out of San Francisco was especially interesting, it's good to see people getting thoughtful about how to efficiently address pedestrian safety problems.