Hierarchies and Intersections

Question 1

What 2 factors must a transport system juggle?

Answer 1

Access and movement.

Question 2

What types of roads have high access?

Answer 2

Local streets

Question 3

What types of roads have high movement?

Answer 3

Freeways, expressways.

Question 4

Which roads balance between both access and movement?

Answer 4

Major arterials.

Question 5

If movement was on the y axis and access on the x, which letter does the curve represent?

Answer 5

It looks like the middle section of an ‘s’

Question 6

What are the key principles of self-explaining roads?

Answer 6

1) Functionality
2) Homogeneity
3) Predictability
4) Forgivingness
5) State awareness

Question 7

What are self-explaining roads?

Answer 7

Roads that make it clear to drivers what road type they are on. They can then adjust their driving accordingly.

Question 8

What are the key defining attributes for street patterns?

Answer 8

• Rectilinear or curvilinear road links
• Grid-like, tree-like (tributary) or radial link patterns
• T or X intersections
• Small cells connected to other cells.

Question 9

What pattern is being pushed currently?

Answer 9

Grid networks called “New Urbanism”

Question 10

Two factors that will influence the road network?

Answer 10

Speed and volumes

Question 11

Will curvilinear designs have slower or faster speeds?

Answer 11

Slower speeds

Question 12

Will networks with shorter links and more intersections have slower or faster speeds?

Answer 12

Slower speeds

Question 13

What will tributary networks do to the traffic volumes?

Answer 13

Limit through traffic along minor streets, but funnel higher volumes onto the top-level streets.

Question 14

What are factors network connectivity should be designed to?

Answer 14

• Shorter travel distances
• Increased number of alternate routes
• Increased opportunity or interactions
• Improved access to public transport, walking and cycling networks
• Good access to final destinations

Question 15

What two key elements are networks comprised of?

Answer 15

Nodes - road/rail intersections/endpoints or terminals/stations etc where transport stops
Links - actual roads/rails

Question 16

What are the two types of link connections?

Answer 16

• Series

- Parallel

Question 17

What are the 7 basic topologies? (the combination of nodes and links in different ways)

Answer 17

• Ring
• Star
• Mesh
• Fully connected
• Line
• Tree
• Bus

Question 18

What are the 5 main types of intersections?

Answer 18

1) Uncontrolled - minor roads
2) Priority - major roads, giveway/stop on minor roads
3) Rotary - roundabout priority
4) Signalised - major conflicted flows are separated in time
5) Grade separated - separation in space of major conflicting flows by overbridges and underpasses

Question 19

What factors are considered when selecting intersection?

Answer 19

1) Efficiency - delays, stops, fuel
2) Safety
3) Other factors - effect of adjacent land, road hierarchy

Question 20

What are the 10 principles of intersection design? pg 69 lol

Answer 20

1) Adequate capacity and approx form of control
2) Reduced conflict points
3) Minimise area of conflict
4) Separate conflict points
5) Give preference to major flows
6) Control veh speed
7) Clearly define veh path
8) Provide adequate sight distance (but not too much)
9) Clear form of control for approaching road users
10) Provide for all road users

Question 21

What is channelisation?

Answer 21

Secondary roads to separate different flows of traffic from the main traffic flow.

Question 22

What are the disadvantages of channelisation?

Answer 22

1) Introduction of an obstruction on the road
2) Restriction of parking/access to property
3) Increased drainage and pavement maintenance problems

Question 23

Classification of roundabouts.

Answer 23

1) Conventional - raised central island, approaches not flared
2) Small - raised central island, approaches flared
3) Mini - flush (small rise), approaches flared.

Question 24

How should roundabouts be designed?

Answer 24

• Adequate entry width
• Adequate circulation space
• Sufficient central island diameter
• Deflection of traffic to the left on entry, promoting rot movement
• Simple layout

Question 25

How are veh speeds controlled at roundabouts?

Answer 25

Kept low with adequate deflection of crossing movement.

• Max safe of 50km/h
• Max safe of 30km/h with bikes and peds