Transport, Accessibility, and Land Use in Urban Environments

TRANSPORT, ACCESSIBILITY AND LAND USE

Definition of Accessibility: Accessibility is defined as the ease of approach to one location from other locations. It is the fundamental measure of how reachable a specific point is within a spatial system.
Components of a Transport System:
- Node: A location where movements originate or end, or a point where changes in transport modes occur (e.g., a bus terminal, a train station).
- Link: The physical or functional connection between two nodes (e.g., a road, a railway track).
- Network: The entire system formed by the collection of interconnected nodes and links.

THE ACCESSIBILITY NUMBER

Definition: The accessibility number represents the number of links necessary to reach the furthest place from a specific node using the shortest possible route.
Interpretation: A lower accessibility number indicates a more accessible location, as it requires fewer links to traverse the network to its most distant point.
Example Calculation Matrix (Nodes A-D):
- Node A: Number of links to reach B ( $1$ ), C ( $1$ ), D ( $1$ ). Furthest node distance is $1$ . Accessibility Number = $1$ .
- Node B: Number of links to reach A ( $1$ ), C ( $2$ ), D ( $2$ ). Furthest node distance is $2$ . Accessibility Number = $2$ .
- Node C: Number of links to reach A ( $1$ ), B ( $2$ ), D ( $1$ ). Furthest node distance is $2$ . Accessibility Number = $2$ .
- Node D: Number of links to reach A ( $1$ ), B ( $2$ ), C ( $1$ ). Furthest node distance is $2$ . Accessibility Number = $2$ .
- Conclusion: Node A is the most accessible because it can reach the furthest node with the smallest number of links ( $1$ ).

CASE STUDY: ACCESSIBILITY NETWORK DATA

Node Distances from Carlisle (Number of Links):
- Carlisle to Manchester: $1$
- Carlisle to Birmingham: $2$
- Carlisle to Tewkesbury: $3$
- Carlisle to Ross: $4$
- Carlisle to Bristol: $4$
- Carlisle to Newport: $5$
- Carlisle to Leeds: $5$
- Carlisle to Sheffield: $4$
- Carlisle to Doncaster: $5$
- Carlisle to Northampton: $3$
- Carlisle to London: $4$
- Carlisle to Maidenhead: $5$
Accessibility Summary Table (Maximum Links to Furthest Node):
- Manchester: Maximum links to furthest point = $4$
- Birmingham: Maximum links to furthest point = $3$
- Tewkesbury: Maximum links to furthest point = $4$
- Ross: Maximum links to furthest point = $5$
- Bristol: Maximum links to furthest point = $5$
- Newport: Maximum links to furthest point = $6$
- Leeds: Maximum links to furthest point = $6$
- Sheffield: Maximum links to furthest point = $5$
- Doncaster: Maximum links to furthest point = $6$
- Northampton: Maximum links to furthest point = $4$
- London: Maximum links to furthest point = $5$
- Maidenhead: Maximum links to furthest point = $6$
Conclusion: Birmingham is the most accessible node in this network as it has the smallest "minimum number of links" ( $3$ ) required to reach its farthest point.

IMPACT OF ACCESSIBILITY ON VARIOUS LAND USES

Residential Land Use:
- Benefits: Provides convenience for residents to travel to work, school, or shops.
- Economic impact: Results in lower transport expenses, which is especially critical for low-income residential areas.
Industrial Land Use:
- Benefits: Locations with superior transport infrastructure reduce the costs associated with acquiring raw materials and distributing finished products to markets.
- Labor market: Highly accessible locations are more effective at attracting a steady labor force.
Commercial Land Use:
- Main Focus: To maximize sales.
- Mechanism: Shops located in convenient, accessible areas attract a higher volume of customers.
Institutional Land Use (e.g., Schools, Police Stations, Hospitals):
- Benefits: Convenient locations ensure that the general public can access essential services easily, allowing for a higher volume of people to be served.
Recreational Land Use (e.g., Cinema, Beaches):
- Cinema: Requires convenient locations to attract customers, functioning similarly to commercial land use.
- Beaches and Country Parks: Must be accessible to the public to facilitate leisure and usage.
Agricultural Land Use:
- Benefits: Farmers require accessibility to deliver fresh and perishable products to the market rapidly to maintain quality.

VIRTUAL FIELD INVESTIGATION RESOURCES

Bus Fandom: Used to determine the number of bus routes and the furthest reachable destinations.
Centamap: Used to analyze land rent for commercial, industrial, and residential buildings.
Google Street View: Provides visual evidence and photos of shops and services for land use pattern analysis.

LAND RENT AND THE CITY CENTRE

The City Centre as a Transport Focus: In urban areas, the city centre is typically the most accessible location because it acts as the primary focus of the transport network.
Land Use Competition: Since all land uses prefer high accessibility and the land area in the city centre is finite, competition for space is most intense in central locations.
Land Value: This competition results in the city centre having the highest land values in the urban area.
Distance-Decay Effect: This principle states that as distance from a point (the city centre) increases, the intensity of any pattern or process decreases. This manifests as:
- Decreased social interaction between people as physical distance increases.
- Lower accessibility and lower land values in locations further from the centre.

BID-RENT THEORY

Definition: Bid-rent refers to the maximum price that a particular land use is willing and able to pay for a location. This is directly dependent on the profits that the land use can generate at that site.
Land Use Distribution: Due to competition, the land use with the highest bidding power (the one that can afford the highest rent) will occupy the most accessible land. Consequently, urban land use distribution is governed largely by the profit-earning potential of different activities.
Numerical Data: Bid-Rent of Land Uses ( $/m^2$ ) by Distance from City Centre ( $km$ ):

Distance ( $km$ )	Shop ( $/m^2$ )	Office ( $/m^2$ )	Industrial ( $/m^2$ )	Residential ( $/m^2$ )
$0$	$120$	$105$	$84$	$68$
$1$	$90$	$87$	$75$	$62$
$2$	$60$	$70$	$66$	$56$
$3$	$31$	$52$	$56$	$50$
$4$	$0$	$35$	$47$	$45$
$5$	$0$	$18$	$37$	$39$
$6$	$0$	$0$	$28$	$34$
$7$	$0$	$0$	$18$	$28$
$8$	$0$	$0$	$9$	$22$
$9$	$0$	$0$	$0$	$17$
$10$	$0$	$0$	$0$	$11$
$11$	$0$	$0$	$0$	$6$
$12$	$0$	$0$	$0$	$0$

LAND USE CHARACTERISTICS AND BID-RENT CURVES

Goods and Services Classification:
- Low-Order Goods/Services: These are cheaper, daily necessities (e.g., groceries). They are purchased or used frequently.
- High-Order Goods/Services: These are expensive items (e.g., luxury goods, specialized services). They are not purchased or used often.
Specific Land Use Dynamics:
- High-Order Retailing: These activities locate in the most central locations to secure the maximum number of customers. They generate high profits and require limited space, allowing them to bid the highest rent. However, their bid-rent falls rapidly as accessibility decreases moving away from the centre.
- Low-Order Commercial Activities (e.g., Offices): These typically locate further from the city centre. They are less sensitive to accessibility than retail but still seek to avoid the highest rents of the absolute centre; their bid-rent curve is less steep than high-order retail.
- Industrial Land Use: These require large amounts of space. Because they cannot afford the high rents of the centre, they locate in less accessible areas further out.
- Residential Land Use: Residential uses bid the lowest rent and are the least affected by accessibility. They occupy the land furthest from the city centre where high-profit commercial or industrial functions cannot justify the costs.
Theory Implications: The price and demand for land are highest at the Central Business District (CBD) and decrease toward the city fringe, resulting in distinct "zoning" of land uses.

LAND USE INTENSITY

Vertical Expansion: To offset high land rents in areas with extreme accessibility, land use intensity increases. This leads to vertical expansion (skyscrapers) and high building density, which is common in the CBD and near major transport nodes.

VARIATIONS AND LIMITATIONS TO BID-RENT THEORY

Hong Kong Context Constraints:
- Physical Constraints: The presence of the harbor, islands, and hilly relief.
- Secondary Centers: The development of commercial centers outside the primary CBD, such as Quarry Bay and Kwun Tong.
- Transport Routes: The influence of specific MTR routes on accessibility.
- Government Planning: The creation of New Towns or internal CBD parks (e.g., Hong Kong Park).
Transport Nodes: Areas around transport nodes also possess high accessibility; their land values are elevated, though generally lower than the city centre.
Polycentric Development: Large urban areas often develop around several centers (transport terminals, rail stations, ports) rather than a single CBD. In Hong Kong, areas like Shatin and Mong Kok serve as diverse centers of growth with high accessibility.

THE BURGESS CONCENTRIC ZONE MODEL (1925)

Basis: Developed by Ernest Burgess based on American cities, specifically Chicago.
The Five Zones:
1. Central Business District (CBD): The most accessible zone with a concentration of commercial activities and the highest land rent.
2. Zone of Transition: Characterized by light manufacturing (industries) and poor-quality housing. It is often occupied by factory workers and immigrants looking for lower rent and proximity to work to save on transport costs (the "Inner City").
3. Low-Class Residential: Working-class homes.
4. Middle-Class Residential: Single-family dwellings.
5. Upper-Class Residential / Commuters Zone: Located in the suburbs with the highest quality housing and high commuting costs.
Limitations of the Burgess Model:
- Ignores physical features (hills, water).
- Does not account for historical context.
- Does not consider urban renewal or gentrification.
- Zones are rarely as clear-cut in reality as they are in the model.
- Does not account for polycentric urban structures.

URBAN DECAY AND RENEWAL

Signs of Urban Decay:
- Worn-out and poorly maintained buildings (e.g., exposed concrete on walls).
- High building density with a lack of open space, community facilities, or recreational areas (e.g., Sham Shui Po).
- Land Use Conflicts: Issues arising from mixed land use, such as industrial/commercial shops (selling gas or electronics) operating below residential flats (e.g., Ap Liu Street, Yau Ma Tei).
- Urban Congestion: Narrow roads and high traffic volume.
Urban Renewal (The 4R Strategies):
1. Redevelopment: Pulling down old, short buildings and replacing them with taller, modern commercial and residential structures.
2. Rehabilitation: Repairing and maintaining existing structures.
3. PReservation: Saving buildings or areas with historical/cultural value.
4. Revitalization: Injecting new life and economic activity into an area.

REDEVELOPMENT CASE STUDIES IN HONG KONG

Argyle Street/Shanghai Street Project (Langham Place):
- Area: $11,976\,m^2$
- Existing GFA: $40,810\,m^2$
- Affected Buildings: $108$ ; Affected Population: $2,603$
Lee Tung Street / McGregor Street Project (The Avenue):
- Area: $8,236\,m^2$
- Existing GFA: $36,534\,m^2$
- Affected Buildings: $85$ ; Affected Population: $1,613$ ; Property Interests: $649$
Tsuen Wan Town Centre Project (Vision City):
- Area: $20,300\,m^2$
- Existing GFA: $56,851\,m^2$
- Affected Buildings: $96$ ; Affected Population: $7,119$
Kwun Tong Town Centre Project (K7):
- Area: $53,500\,m^2$
- Existing GFA: $96,104\,m^2$
- Affected Buildings: $24$ ; Affected Population: about $4,763$
- Affected Property Interests: about $1,653$ ; Households: about $1,401$

EVALUATION OF URBAN REDEVELOPMENT

Pros of Redevelopment:
- Increases floor space in urban areas, maximizing the use of valuable land.
- Improves the urban environment by providing an opportunity for wider roads and more open spaces.
- Introduces modern building designs and greenery (e.g., vegetation walls in Tsuen Wan).
- Provides new social facilities (e.g., the SAGE Tsuen Wan District Elderly Community Centre).
- Creates job opportunities, specifically in the retailing industry.
- Improves connectivity via footbridges between buildings.
Cons of Redevelopment:
- Relocation of low-income residents who may not be able to afford the new residential units.
- Loss of local heritage and "collective memory."
- Gentrification: The displacement of lower-income businesses and residents by higher-order commercial venues and wealthier residents (e.g., the shift from Lee Tung Street's traditional printing shops to high-end retail like Lee Tung Avenue).