|Technology Transfer Series|
|Number 181||May 1998|
Public officials are constantly on the lookout for new ways to make the nation's roadways safer for walkers. With increasingly scarce funds, however, it simply is not possible to implement many of these ideas if they must be applied to an entire commun-ity. The zone process provides a systematic method for targeting pedestrian safety improvements in a cost effective manner. It involves defining relative-ly small geographic areas, or zones, where a relatively large proportion of the problem occurs. Then, a countermeasure program is applied only in the selected zones, targeting the locations with the biggest crash problems.
The National Highway Traffic Safety Administration (NHTSA) and the Federal Highway Administration (FHWA) sponsored a research study to apply the safety zone concept to reducing crashes involving older (65+) adult pedestrians. That study, released earlier this year, developed procedures for defining pedestrian safety zones, and developed, implemented, and evaluated a countermeasure program in Phoenix, Arizona and Chicago, Illinois (see Traffic Tech 174, March 1998). Older pedestrian crashes were reduced by more than 46 percent in target zones.
As a second part of the study, Dunlap and Associates prepared a concise how-to document, Zone Guide for Pedestrian Safety. The Guide describes step-by-step procedures officials can use in applying the zone process to their community's pedestrian safety problems.
Steps In Defining Zones
Defining Zones The first step is to pick the pedestrian crash problem that the community wants to address. Determine if there are excessive pedestrian crashes involving young children, working adults, or maybe the elderly. Then, map the pedestrian crashes either manually or with a computerized mapping system, if one is available.
Since most pedestrian crashes occur within one mile of the victim's home or place of business, circular zones with a radius of one mile are good geometric choices. Decide on a minimum number of crashes within a particular zone for your community. These rates will vary by the size of your community. Linear or rectangular zones that meet a defined rate can also be used.
Finally, calculate an efficiency measure for the selected zones to determine if it is practical to apply countermeasures in the zones. This is really just a calculation of the percentages of both crashes and land area. If the ratio of the percent of the problem to the percent of the land area covered in the zones is much less than three, the zones may need to be reexamined to try to improve their efficiency. An efficiency ratio of three to one or higher (for example, in Phoenix 54.8 percent of the 65+ year old crashes occurred in 4.6 percent of the jurisdic-tion's land area) will almost certainly have a good benefit.|
Once the zones are selected, they must be examined to determine how they can be used. The problems and resources in each zone need to be identified. Program activities need to be selected, developed as necessary, implemented, and monitored.
The first step here is to review each zone to assess the pedestrian safety problems that exist and the resources that are available to help solve the problem. Start with a review of the police report for each zone crash to determine the nature of the crash and factors that might have caused it. Then drive or walk through the zones to identify where engineering improvements can be made. The Guide includes checklists for these activities.
Activities that can be applied in defined, small areas are best suited for zoning. Some examples are: