Welcome to “Research Recap,” our series highlighting recent reports, studies and other findings in sustainable transportation policy and practice, in case you missed it.

Bike Helmet Benefits

The debate on the safety benefits of bike helmets rolls on with new controversial research findings. Dr. Rune Elvik of Norway’s Institute of Transport Economics calculated the head injury risk reduction from wearing helmets to be 43 percent, as compared to the previous research finding of 60 percent.  The new statistic, already generating controversy, attributes the decrease in head injury risk reduction in part to helmets’ increasing the risk of neck injuries. TheCityFix blogger Jonna McKone highlighted the bike helmet controversy in a post earlier this year, which included a Q&A with Mikael Colville-Anderson, a bike activist and writer.

Teen Car Accidents

According to a new study on teen drivers, the top three causes of teen driving accidents are the following:

• Lack of scanning needed to detect and respond to hazards
• Driving too fast for road conditions (for example, driving too fast to respond to others or to successfully navigate a curve)
• Distractions by something inside or outside the vehicle

As motor vehicle accidents are the number one cause of teen deaths in the United States, this research conducted by the Children’s Hospital of Philadelphia and State Farm is information that demands action. In advocating teen driver awareness, the U.S. Department of Transportation points out, “getting teen drivers to stay focused on driving and not on texting or talking will only help improve that critical awareness.”

Carbon Consumption in Cities

The carbon emissions of cities are more linked to the income of their inhabitants than to city density, determined a new study by Jukka Heinonen and Seppo Junnila from Aalto University, Finland.  The researchers examined the two largest metropolitan areas in Finland, Helsinki and Tampere, implementing a unique research model that focuses on where emissions are consumed, as opposed to the traditional research model of where emissions are produced. The study also found that the largest contributor to city dwellers’ carbon footprints are heat and electricity.

Roadway Safety

A new study assessing the safety of various roadways found that freeways and center-city mainstreets generate the lowest number of vehicle accidents, and highways with intermittent traffic lights create the most accidents.  The reasons attributed to the low number of accidents on freeways and mainstreets are a low number of potential intersections and low vehicle speeds, respectively.  The high volume of accidents on highways was attributed to the combination of high speeds and high roadway access.