C05

Research Abstracts on Spatial Information ScienceCSIS DAYS 2015

Relation between Urban Traffic Accidents and Urban Structures from Spatial Perspective
Niloofar Haji Mirza Aghasi
Division of Spatial Information Science, Graduate School of Life and Environmental Sciences,
University of Tsukuba
Email: <nia922@yahoo.com>
later dispersion. The insight that travel speed isdependent on factors such as road type, levels ofcongestion, and drivers personal speed preferences,suggest that the relationship between speed limits
and travel time is far more complex than mostdrivers are willing to admit. Road type variationsclearly show that in contrast to many cities in theworld, Tehran’s highways and expressways are not
the most dependable for driving. The finding thatareas with higher levels of social deprivation haverelatively higher casualty rates is also consistent withother findings, although this effect is less stronger
when only motorized casualties are considered. I
have analysed many of the road and accident
characteristics that would be likely to vary
Urbanized between areas. It might be that people
with lack of traffic’s knowledge tend to locate inareas with more unsafe traffic. Increased road length
was associated with increased serious injuries,
especially for highways, which were also associatedwith increased slight injuries. Further analyses of
Tehran’s accident data can exploit additional spatial
relationships. This includes potential spatial
autocorrelation that can help identify similar
unidentified factors between areas that affectcasualties. Time series data would also allow a more
analytical of changes over time and would enable to
avoid problems of heterogeneity in the data. Moredensely populated areas, with few numbers ofhighways and freeway and traffic limitation zone
and traffic limitation boundary will tend to havefewer dangerous accidents which are fatal accidents,
particularly while areas with higher employment
density and more highways and freeways have more
traffic casualties. During the rush hour of thecongestion, posted speed limits and are often
believed to have little effect on driving speed, except
during the build-up of queues and their later
dispersion. Land use category, urban dense andincreased road length was associated with increased
serious injuries, especially for highways, which werealso associated with increased slight injuries.

(1) Motivation: This study gives an insight into theurban traffic accident condition of the Tehran cityand shows out the most potentially accidents prone
roads in the Tehran urban areas. According to themethodology of this study time is an importantfactor which contributes to Tehran’s urban accidents.
The temporal analysis aims to discover the relativerisk pattern temporally and can be used as
prerequisites for spatial analysis targeting spatial
patterns in different time periods. The analysis isbased on different primary and secondary data
sources, which include locations of accidents andattributes such as date, reason, kind, etc.
(2) Approach: The main objective of this study isnecessary therefore to have an understanding structureof urban and accidents for improving safety on theroads which will be done with GIS as GIS is acomprehensive management tool for traffic safety.
(3) Results and Discussion: The analyses have utilized
highly disaggregate spatial units for an analysis ofarea specific variables associated with urban traffic
accidents traffic. Findings suggest that urbanized,
more densely populated areas, with few numbers ofhighways and freeway and traffic limitation zone
will tend to have fewer dangerous accidents which isfatal accidents, particularly while areas with higher
employment density and more highways andfreeways have more traffic casualties. The first
effect may be cause to reduced speeds and higher
levels of congestion or possibly the lower design
speeds of roads in dense areas such as city centers.
The next issue may be due simply to increased levelsof street activity in city area with more exercise.
Results suggest that increasing speeds in urbanizedareas by reducing congestion may have adverse
safety consequences. Granting to the accident data
and this study, travel time may be more dependent
on congestion and road qualification and geometricelements, than posting on the speed limits. During
the rush hour of the congestion, posted speed limits
and are often believed to have little effect on driving
speed, except during the build-up of queues and theirFigure 1: Spatial Extent of Study Area

Figure 2: Tehran Urban Development- 37 -Figure 3: Tehran’s Accidents Density