Summary of "Pedestrian injuries due to collisions with bicycles in New York and California&quot

Research conducted by Peter Tuckel, William Milczarski, and Richard Maisel for the Journal of Safety Research called "Pedestrian injuries due to collisions with bicycles in New York and California," analyzed the relationship between pedestrians and cyclists and their collision and injury rates. Specifically, these researchers look into:

1. How frequently collisions occurred between pedestrians and cyclists?

2. Whether or not that number of collisions has changed over time?

3. What pedestrian (in terms of age, gender, race/ethnicity, and place of residence) is most likely to be present in these collisions with cyclists?

In order to answer these questions, the researchers used hospital records from patients who were injured as a result of pedestrian-cyclist accidents from New York (separately including New York City as its own category) and California; two states with large population sizes and immense biking popularity. The data, however, did not include information about pedestrians who visited walk-in clinics or their own physicians. Nevertheless, within the patient-level hospital records from New York (beginning in 2004 and ending in 2011) and California (beginning from 2005 and ending in 2011), age, sex, race, place of residence, and the patient's diagnoses were collected about pedestrians injured as a result of collisions with cyclists.

In order to understand the effect of each variable - age, sex, race, place of residence, and year - two analyses we conducted: one for injuries that required patients to be admitted to a hospital, and another for injuries that did not require patients to be admitted. The same set of calculations were applied to each category (inpatient vs. outpatient); specifically, injury rates were calculated by counting the number of pedestrians affected by a collision with a cyclist in a specific year, who were in a specific demographic, at a certain location. This number would then be divided by the total population for that certain year, demographic, and location and then multiplied by 100,000.

Pedestrians injured by cyclists from 2004 to 2011. Graph from the Journal of Safety Research.

As a result of the calculations, researchers found a majority of collisions occurred between 2004 and 2008 at a stable or steady increase but began to decline thereafter, occurring less frequently by 2011 in all three locations. Additionally, in all three locations, men were the more frequently injured by collisions than women and ages 0 to 14 was the most common age group. The most common injury as a result of cyclist-pedestrian collisions was to the head and neck. Race did not appear to have a consistent pattern like gender and age among the three locations, though.

In terms of inpatient and outpatient analysis, it appeared more inpatient and outpatient reports were found in New York and New York City. Additionally, the ages of 0-14 were more heavily found as outpatients with a significant increase over time; whereas, for inpatients, ages 0-14 had dramatically lower rates of injury than older individuals.

The results from this study are slightly startling because as the number of collisions has declined in more recent years, the number of cyclists has steadily increased. The researchers offer a few possible explanations for this phenomenon.

One explanation is that the number of children playing outside has significantly decreased. Therefore, the more time children play inside, the less opportunity they have for being in a collision with a cyclist. Another possible explanation is the increased infrastructure for bike safety in these areas. This explanation has more empirical research to back its claim as New York City, who founded the first protected bike lane project in the U.S. from 8th and 9th Avenue in Manhattan, experienced a 35% decrease on 8th Avenue and 58% decrease on 9th Avenue regarding injuries to all street users. The researchers also suggested the bike safety education may have also contributed to the decrease in cyclist-pedestrian collisions.

As the research notes, there are numerous studies regarding pedestrian and motor vehicle injury; however, there is little to none - the research mentions one other study in Germany - that focuses on the relationship between pedestrians and cyclists injuries. This research concludes with a call to action for further research in more locations in order to protect the future safety of pedestrains and cyclists.