Chapter 10

Question 1

Three rules to minimise cost of roads:

Answer 1

1. Minimise length
2. Specialise – different orders of roads – different functions – different access and exit points impacting on flow
3. Gentle gradients and gentle curves – higher speeds

Question 2

Transport networks provide accessibility and mobility: define and explain each concept

Answer 2

Accessibility – number of available opportunities within and given time/distance to gain access to transport network (how many points along point A and B can get onto road, bus, train) (physical accessibility): function of transport network, land use, mode (higher accessibility for minibus than rail)
o Physical accessibility onto and to
o economic accessibility
o city-wide

Mobility – ability to move between activity sites (how many activity sites can you reach given transport network) can you get to work, shop, education within time frame and distance: function of mode, land use and network

Question 3

Street layout impacts both accessibility and mobility, but impact differs:

Answer 3

• Lower order road – more accessibility, may lead to lower mobility
Design of networks should focus on providing both accessibility and mobility:
• Each level of road provides a function and drains traffic to higher order roads and ultimately highways

Question 4

Some characteristics of roads

Answer 4

Streets provide basis for other infrastructure (electricity cables, drainage

Roads are most demanding in terms of space and cost and are sensitive to alignment

Roads are fundamental to usefulness and quality of the locations they border on , must be accessible – especially in developing countries

Question 5

Four types of road layout

Answer 5

• Suburban
• Grid
• Radial
• Organic

Question 6

As you move from lower order streets to higher order streets accessibility generally decreases but mobility increases. Always a trade-off between the two

Answer 6

Study figure in notes

Question 7

Urban roads can be classified in four categories:

Answer 7

1. Accessibility
2. Mobility
3. Cost (capital and user)
4. Operational characteristics

Question 8

discuss classification of roads according to accessibility, mobility, cost and operational characteristics

Answer 8

All the road types mastered

Question 9

Characteristics of local roads:

Answer 9

1. Accessibility - Very High
2. Mobility - Very low
3. Cost (capital and user) - low cost to build, user cost influenced by number of stops
4. Operational characteristics - low speed (45 or lower), stops every 0.5 km

Question 10

Characteristics of collector streets:

Answer 10

1. Accessibility - High
2. Mobility - Low
3. Cost (capital and user) - Higher build cost – more lanes as multiple lanes of traffic converge, higher user cost at peak hours due to congestion
4. Operational characteristics - speed 60, stops every 0.5+-

Question 11

Characteristics of Central business district roads

Answer 11

1. Accessibility - High
2. Mobility - Low
3. Cost (capital and user) - Lower cost of building, higher running costs
4. Operational characteristics - speed 60-80, stops 05-1km, robots

Question 12

Characteristics of Freeways

Answer 12

1. Accessibility - Very low
2. Mobility - Very high
3. Cost (capital and user) - Cost high to build, many lanes, user cost low due to optimal speed
4. Operational characteristics - speed 100-120, no stops

Question 13

Characteristics of Arterials

Answer 13

1. Accessibility - Low
2. Mobility - High
3. Cost (capital and user) - Cost high to build, user costs higher in peak congestion, lower due to optimal speed
4. Operational characteristics - robots, speed 80, stops 1-2km

Question 14

Service level – focus on explaining service level C

Answer 14

notes