· Identify a policy that is not usually intended to be a health policy but that you think may have important health implications.
Urban planning policies are often not considered as health policies, but they can have significant health implications for groups of individuals. One example is city policies regarding traffic signal cycle lengths, which determine the length of time that an individual has to cross an intersection at a traffic signal before the light changes.
· Describe why an evaluation of that policy is informative (e.g., determining effects of the policy, or primarily a test of hypothesized mediators).
Evaluation of these policies is important to determine whether the resulting traffic signal cycle lengths minimize the risk to pedestrians of sustaining a traffic injury.
· Specify the outcomes and populations you think most affected or least affected by the policy.
These policies are particularly important for citizens at the extremes of age (children and the elderly), those who require mobility assistive devices (e.g. wheelchairs and canes), and those who have hearing/visual impairments. These populations may require more time to safely navigate congested intersections, and inappropriately timed traffic signal cycles put them at risk of injury.
· Propose a study design to evaluate the policy.
The primary outcome of interest would be injury rates at intersections relative to the volume of traffic, built environment characteristics, and the length of the traffic signal cycle. The study could be conducted as a comparison of injury rates before and after a change was made to the traffic cycle signal length (if any changes were being planned). Alternatively, one could do a comparison between injury rates at intersections with similar traffic volume & built environment characteristics (e.g the presence of turn lanes, bike lanes, and raised medians) but different traffic signal cycle length.
In addition to this quantitative study, I think it would be interesting to do a qualitative survey of members of the vulnerable populations described above to assess whether the routes they choose as pedestrians are impacted by perceived dangers at certain intersections. This analysis would give a richer assessment of the ways in which urban planning policies inadvertently impact the daily lives of certain groups of people.
· Describe biggest challenge to implementing and drawing inferences about the impact of the policy on health.
The challenge with implementing changes to urban planning policies is that there are multiple points of view and competing interests at work when the policies are designed. Pedestrian safety is a priority to city officials, but so is maintaining efficient flow of vehicles, decreasing traffic congestion, and providing adequate space for cyclists and riders of other modes of transportation. These priorities frequently conflict with one another, making policy implementation complex.