Streets
play significant roles in meeting multiple sustainability objectives. This
research addresses Abu Dhabi’s and Dubai’s street connectivity at the
neighborhood (local) and city (global) scales. It focuses on two parameters of
street network analysis: efficiency and centrality. Efficiency is evaluated in
terms of directness, noting that network designs that provide short and direct
access between origins and destinations are more efficient. Centrality is
evaluated using graph theory metrics that enable the identification of high-
and low-accessibility locations within networks. Research has shown that
network centrality metrics are useful for capturing location advantage, a
significant factor for land use distribution. An understanding of centrality and
its impacts makes it possible to plan land uses that bring destinations closer
to residences, an important factor in environmental, economic, and social
sustainability. The proposed study will offer scientifically grounded
strategies and policies that will enable various stakeholders to design more
sustainable street systems and land uses.
Analysis for
local scale has been completed for 13 neighborhoods. Six of these neighborhoods
namely Al Bahya, Al Falah, Baniyas, Khalifa City, MBZ, and West Island AD are
located in Abu Dhabi. While, eight neighborhoods namely Al Barsha, Al Satwa, Al
Quoz, Al Rashidiya, Al Warqa, Creek area, and Jumeirah are located in Dubai.
The evaluation of accessibility of the built environment was accomplished
through the use of computational tools.
The project
utilizes a novel methodology that uses conventional morphological analysis
(e.g., mapping and quantification of blocks, plot sizes, building density, and
land uses) to build a foundation for conducting advanced computational studies.
Spatial network analysis, namely Multiple Centrality Assessment and Urban
Network Analysis (UNA), is used to evaluate various performance indicators that
take into account spatial relationships and connections between different
locations in urban space. Centrality assessment metrics like Reach,
Straightness, Gravity, and Betweenness are calculated for each of the selected
neighborhoods. For each neighborhood, these metrics are calculated for
different radii like 400 meters, 800 meters, and 1600 meters for the local
scale analysis. In addition, global scale analysis is carried out for the
chosen neighborhoods to determine how metrics like reach, straightness,
betweenness, etc. vary with increasing radii of 3,000 meters and 6,000 meters.
In addition, advanced metrics like Closest Facility is also computed for all
neighborhoods which provides new insights about the patronage of a destination
like potential number of visitors for a commercial outlet. Advanced Betweenness
is calculated which takes into account the population data associated with the
origin points (i.e. estimated number of people living in a plot). Order and
adaptability of street networks are also being measured/investigated. Order of
street orientation is represented as the Shannon
entropy. This value represents the level of order/disorder. The smallest value
of φ is 0 which means complete disorder, while φ =1 means a perfect order. Adaptability of street network is
characterized by a semi-lattice system which is in turn defined as
overlapping. The degree of movements on
a street segment represents levels of overlapping activities in a street
network. This value of movement is the value of betweenness centrality.
For each
neighborhood, maps are prepared for the illustration of aforementioned metrics
and the spatial distribution of its values. First, local scale analysis is
conducted at three scales- 400 meters, 800 meters, and 1600 meters
corresponding to 5 minutes, 10 minutes, and 20 minutes’ walk respectively.
Second, global scale analysis is conducted at 2000 meters, 5000 meters, and
10,000 meters. Broadly, the analysis is classified into two approaches- 1)
All-to-all where all plots are considered as origins, and all plots simultaneously
considered as destinations, and 2) Targeted Destinations where public
facilities like hospitals and schools, or points of interest like parks and
mosques, are set as destination points, while residences are set as origins.
Four types of target destinations are used in this project namely Commercial
(i.e. grocery stores, malls, laundry, typing center, etc.), Parks (i.e. big
parks to small children parks), Educational (i.e. nurseries to universities),
and Mosques. Furthermore, advanced spatial analysis was conducted twice for
each metric in ArcGIS and Rhino with UNA tool; once by adding alleyways network
into analysis, and once without the alleyway network.
Articles
Alawadi, K.,
Khaleel, S., & Benkraouda, O. (2020). “Design and planning for
accessibility: lessons from Abu Dhabi and Dubai’s neighborhoods”. Journal
of Housing and the Built Environment, 1-34. https://doi.org/10.1007/s10901-020-09763-3
2) Alawadi, K.,
Alameri, H., & Scoppa, M. (2020). Reclaiming alleyways to improve network
connectivity: Lessons from Dubai’s neighborhoods. Journal of Planning
Education and Research. https://doi.org/10.1177%2F0739456X20931907
3)
Alawadi, K., Khanal, A., El Doudin, A., & Abdelghani, R.
Revisiting Transit-Oriented Development: Alleys as Critical Walking
Infrastructure. Transport Policy. https://doi.org/10.1016/j.tranpol.2020.11.007
Alawadi, K., Khanal, A., Al Hinai, S. Rethinking suburban design: streets v/s alleys
in improving network connectivity. Journal
of Urban Design. https://doi.org/10.1080/13574809.2021.1921570
Alawadi, K., Hong Nguyen,
N., Alrubaei, E., & Scoppa, M. Streets, density, and the superblock: neighborhood planning units and street
connectivity in Abu Dhabi. Journal of Urbanism: International Research on
Placemaking and Urban Sustainability https://doi.org/10.1080/17549175.2021.1944281
Alawadi, K., Hong Nguyen. N., & Mariam J. The Edge and the
Center in Neighborhood Planning Units: assessing permeability and edge
attractiveness in Abu Dhabi. Transportation,
1-29. https://doi.org/10.1007/s11116-021-10257-6
|