Hasan Ziari
Assistant Professor Department of Civil Engineering,
Iran science and Technology University, Tehran, Iran
Mohammed M. Khabiri
Ph.D. Student and Lecturer
Department of Civil Engineering,
Vali-Asr Rafsanjan University, Iran,
Tel: +98 21 73914142,
E-mail: [email protected]
People are important in towns. They are the foundation of the social and economic processes that drive the urban system and sustain the urban framework[1]. The Pedestrian & Bicycle Safety Program focuses on identifying problem areas for pedestrians and bicycles, developing analysis tools that allow planners and engineers to better understand and target these problem areas, and evaluating counter- measures to reduce the number of crashes involving pedestrians and bicycles.
We should be taking the steps to try to interest users that are not GIS technical people, in the use of ArcView in a desktop application. One of the projects that has been developed, is making accident data obtained from Tehran available to ArcView users. Safety is a driving factor in access management and the crash reports are the best indicator of the lack of safe roads. This paper presents the development and findings of crash data from police reports and how they are being used in a Geographic Information System (GIS).
Geographic Information System (GIS) software turns statistical data, such as accidents, and geographic data, such as roads and crash locations, into meaningful information for spatial analysis and mapping. In this project, GIS-based analytical techniques have been applied to a series of pedestrian and bicycle safety issues:
- Safe routes for walking to school.
- Selection of streets for bicycle routes.
- High pedestrian crash zones.
In addition, tools were developed to make it easy for non-GIS specialists to perform similar analyses. These software will provide insight into how the GIS can be used to improve pedestrian and bicycle safety, demonstrate the safety analysis tools using real-world data, and provide the software code that users can adapt to fit their particular needs. The minimum requirements to run the safety analysis tools include Arc View 3.0 or higher; Network Analyst extension and Windows offices.
Route to school and bicycle applications are not in traditional roadway inventory files maintained by local transportation agencies. This data should be collected along with other roadway inventory information during database updates.
This tool uses grid and map algebra to generate a contour map identifying areas of high crash occurrence, as determined by crash density, and clusters of crashes involving pedestrians or bicyclists. Summary statistics of selected zones can be generated and displayed in table or chart form.
Traffic Characteristics and Pedestrian Safety Problem in Iran
The Iran has a population of approximately 69,000,000 people. We have a slow but steady growth of about 1.4% .The Inner Ministry is responsible for transportation planning in the urban area. To assure the safety of the traveling public as the population grows, we are looking at safety management standards for our main arterials.
Iranian cities are characterized by heterogeneous traffic (a mix of non-motorized and motorized modes of transport) and mixed land-use patterns. Non-motorized vehicles are owned and used by a large section of the population. Car ownership rates in Iran is low compared to those of North America and Organization for Economic Cooperation and Development countries. In 1993 car ownership was 170 cars per 1,000 residents in Iran, compared to 561 cars per 1,000 residents in North America, and 366 in OECD countries[2].
A Road traffic accident is a serious problem in Iran. Road accident fatalities and injuries are increasing with no sign of being under control. Fatalities increased by 28% compared to 2000. On average, fatalities are increased by 20% per year. Fatality rate was 151 fatalities per million inhabitants in 2001. Pedestrians fatality rate in Iran is high when compared to international statistics. The rate in Europe is 14 pedestrians per million inhabitants; it is the lowest in the world.
General accident statistics in Iran do not provide such level of details to make any comparison. However, still it is possible to indicate that pedestrian accidents, regardless of age groups, occur more frequent on the afternoon, on daytime and in dry weather conditions Generally, children are considered a high risk pedestrian group. This may be due to. Children conception and perception of traffic situations is not always well-developed .Table 1 shows a perspective of safety problem in Iran.
Table1- Growth of accident rate between 2001-2003 in Iran [3]
Advantages of This Program
Safe Routes to School
This program generates a walking route and associated directions for:
- The shortest route to school,
- The safest route based on hazards associated with various road and traffic elements or
- The preferred route (based on preferences selected by the user). The potential users of this tool are parents, school transportation officials, planners, engineers, or others responsible for the safety of schoolchildren. The users will be able to choose routes with stops along the way (e.g., a friend’s house) or routes that avoid certain locations.
Bicycle-Compatible Routes
This tool provides two output options. The first option is similar to the safe route to school. This option generates a map and directions for the quickest or best bicycle route for an individual trip between user-selected points. The best route is based on the bicycle compatibility index (BCI), which is a calculation of the comfort of each street segment based on roadway and traffic characteristics. The comfort index is based on ratings by more than 200 bicyclists. The second output option is a color-coded map based on the bicycle compatibility index of all streets in a study area. This option can assist bicycle coordinators, planners, traffic engineers, and others in designating bicycle routes and identifying bicycle facilities that may need improvement.
High Pedestrian Crash Zones
This program uses grid and map algebra to generate a contour map identifying areas of high crash occurrence, as determined by crash density, and clusters of crashes involving pedestrians or bicyclists. Summary statistics of selected zones can be generated and displayed in table or chart form.
In general, this has been an enviable project. There have been no complications in the use of the data and the conversion to the GIS system. The conversion of the data was fairly seamless, and the accident points matched well, generally within 12m, of the road centerline.
The future plans for the data include relating the two digit street code to the actual arc segments and tying this to the traffic count information. This will allow us to calculate accident rates rather than using raw crash numbers for analysis.
Overall, the data received has been an invaluable aid in the planning process. The data worked out well for the safety management project and continues to be a valuable tool for applications other than originally intended. This was an important lesson to us in working with other agencies and departments.
Development of the Data
The number and cause of collisions are the main determinate of the safety of the roadway. Therefore, we need to be able to examine, in depth, the collisions that occurred along arterial roadways to determine if they could be prevented by having access control measures in place.
The Inner Ministry is responsible for collecting all of the accident information in Iran. Using an extract of the City’s database in files. The files were then put into ArcView GIS to create maps of specific locations or to use the databases for queries. The result could then be displayed graphically as well as in tabular form. The GIS also allows inquires on the map that is linked to the database.
The Iranian Inner Ministry had been producing an accident report annually. This report contained limited information. The type and cause of the crashes were not included. Plus the location of the accidents was summarized and not detailing specifically where the crashes had occurred. The next step in the search was the Iranian Ministry of Road Transportation, Safety Branch. This office receives all accident reports Countrywide. Iran is fortunate in that all police agencies including highway patrol and municipal police use the same traffic accident report form.
Construction Data Base
The decision was made to use data as the basis for accident analysis. This data covers the desired geographic area and includes all police agencies. An accident must be located within 15m on a map from the report, and it is given an x ,y coordinate with a digitizer.
If the crash damage is less than $50 it is not included in the database. This eliminates the small crashes from being reported and therefore would not be in the database. Thirdly, private property accidents are not included unless related to an access or intersection onto a public roadway.
The main database is called base. This contains all of the general information about the accident such as date, time, conditions, and if available, the coordinates. The other databases called vehicle, driver, and person detailed each of these areas of the crash. These four databases contain a common “Key” field that keeps the data elements tied together.
Annual updates are obtained to keep the data current. The type of information that are obtained included such items as:
- the number of vehicles involved
- the number of injuries
- number of fatalities
- violations issued
- type of and severity of injuries
- type of accident
- activity prior to the accident
- human contributing factors
This level of detail allowed the more in depth analysis that was necessary for the project.
The GIS platform allows for a visual map connection to the database. Figure 2 shows the accident locations across a city and the database connected to the map. This allows queries to be made either from the map or from the database. This system allows various maps and charts to be made that go into the annual report production.
The base database is now useable in the GIS to use for queries, buffering, and other types of analysis. The three other databases driver, vehicle, and person are then linked in ArcView to the base. This allows all four databases to respond to analytical queries.[4]
Figure1. Road and alley map of a district of Tehran [5]
Figure2. The accident locations across in a city and the database connected to the map.[4]
Conclusion and Recommendations
In general, this has been an enviable project. There have been no complications in the use of the data and the conversion to the GIS system. The conversion of the data was seamless, and the accident points matched well, generally within 12m, of the road centerline. This will allow us to calculate accident rates rather than using raw crash numbers for analysis.
Overall, the data received has been an invaluable aid in the planning process. This was an important lesson to us in working with other agencies and departments.
- Traffic safety education in Iran is in urgent need of proper attention. The role of the School should be over emphasized. Parents are currently the main source of information
- Planners should be aware of pedestrian needs and behavior in traffic. This knowledge Will guide them to provide safe pedestrian facilities.
- Pedestrian road infrastructure in Iran is in need of modernization to provide a safe Traffic environment to the young generation.
Figure 3. A ArcView program and database table of accident statistical software[4]
