4.1 Design of Highways and Railways

Question 1

What are the 11 factors influencing highway design?

Answer 1

1. functional classification
2. design hourly traffic volume and vehicle mix
3. design speed
4. design vehicle
5. cross section of the highway, such as lanes, shoulders, and medians
6. presence of heavy vehicles on steep grades
7. topography of the area that the highway traverses
8. level of service
9. available funds
10. safety
11. social and environmental factors

Question 2

Highways are classified according to their functions in terms of ______.

Answer 2

the service they provide

Question 3

______ facilitates a systematic development of highways and the logical assignment of highway responsibilities among different jurisdictions.

Answer 3

highway functional classification

Question 4

Highways and streets are categorizes as _____ or ____, depending on the area in which they are located which affects the type of land use and population density, which in turn influences travel patterns.

Answer 4

rural, urban roads

Question 5

Within the classification of urban and rural, highways are categorized into 5 groups: ____

Answer 5

1. principal arterials
2. minor arterials
3. major collectors
4. minor collectors
5. local roads and streets

Question 6

This system of highways serves the major activity centers of the urban area and consists mainly of the central business districts (CBSs) of urbanized area.

Answer 6

urban principal arterial system

Question 7

What are the 3 subclasses of urban principal arterial system based mainly on the type of access to the facility?

Answer 7

1. interstate
2. expressways
3. other principal arterials

Question 8

_____, with fully-controlled access and grade separated interchanges.

Answer 8

interstate

Question 9

____, which have controlled access but may also include at-grade intersections.

Answer 9

expressways

Question 10

____, with partial or no controlled access.

Answer 10

other principal arterials

Question 11

Streets and highways that interconnect with and augment the urban primary arterials are classifed as _____.

Answer 11

urban minor arterials

Question 12

This system serves trips of moderate length and places more emphasis on land access than the primary arterial system.

Answer 12

urban minor arterial system

Question 13

All arterials not classified as primary are included in this class.

Answer 13

urban minor arterial system

Question 14

The main purpose of streets within this system is to collect traffic from local streets in residential area or in central business districts (CBDs) and convey it to the arterial system.

Answer 14

urban collector system

Question 15

Thus, collector streets usually go through residential areas and facilitate traffic circulation within residential, commercial, and industrial areas.

Answer 15

urban collector street system

Question 16

This system consists of all other street within the urban area that are not included in the three systems described earlier.

Answer 16

urban local street system

Question 17

The primary purposes of these streets are to provide access to abutting land and to the collector streets.

Answer 17

urban local street system

Question 18

This system consists of a network of highways that serves most of the interstate trips and a substantial number of intrastate trips.

Answer 18

rural principal arterial system

Question 19

Virtually all highway trips between urbanized areas and a high percentage of trips between small urban areas with populations of 25,000 or more are made of this system.

Answer 19

rural principal arterial system

Question 20

The system is further divided into freewars (which are divided highways with fully controlled access and no at-grade intersections), and other principal arterials not classified as freeways.

Answer 20

rural principal arterial system

Question 21

This system of roads augments the principal arterial system in the formation of a network of roads that connects cities, large towns, and other traffic generators, such as large resorts.

Answer 21

rural minor arterial system

Question 22

Travel speeds on these roads are relatively high with minimum interference to through movement.

Answer 22

rural minor arterial system

Question 23

Highways within this system carry traffic primarily within individual conties, and trip distances are usually shorter than those on the arterial roads.

Answer 23

rural collector system

Question 24

What are the 2 subdivisions of rural collector system?

Answer 24

1. rural major collector roads
2. rural minor collector roads

Question 25

Routes under this system carry traffic primarily to and from county seats and large cities that are not directly served by the arterial system.

Answer 25

rural major collector system

Question 26

The system also carries the main intracountry traffic.

Answer 26

rural major collector system

Question 27

This system consists of routes that collect traffic from local roads and convey ito to other facilities.

Answer 27

rural minor collector system

Question 28

One important function of minor collector roads is that they provide linkage between rural hinterland and locally important traffic generators such as small communities.

Answer 28

rural minor collector system

Question 29

This system consists of all roads within the rural area not classified within the other systems.

Answer 29

rural local roads system

Question 30

These roads serve trips of relatively short distances and connect adjacent lands with the collector roads.

Answer 30

rural local road system

Question 31

What are the 5 highway design standards?

Answer 31

1. design hourly volume 2. design speed 3. design vehicle 4. cross-section elements 5. right of way

Question 32

____ is the projected hourly volume that is used for design.

Answer 32

design hourly volume

Question 33

This volume is usually taken as a percentage of the expected ADT on the highway.

Answer 33

design hourly volume

Question 34

____ is defined as a selected speed to determine the various geometric features of the roadway.

Answer 34

design speed

Question 35

_____ depends on the functional classification of the highway, the topography of the area in which the highway is located, and the land use of the adjacent area.

Answer 35

design speed

Question 36

What are the 3 groups topography is generally classified into for highway design?

Answer 36

1. level/flat 2. rolling 3. mountainous terrain

Question 37

A _______ is selected to represent all vehicles on the highway.

Answer 37

design vehicle

Question 38

What are 3 characteristics used to establish the design standards of the highway; design vehicle.

Answer 38

1. weight 2. dimensions 3. operating characteristics

Question 39

The vehicle type is selected as the design vehicle is _______.

Answer 39

the largest that is likely to use the highway with considerable frequency

Question 40

What are the 3 guidelines apply when selecting a design vehicle?

Answer 40

1. when a parking lot or a series of parking lots are the main traffic generators, the passenger car may be used. 2. for the design of intersections at local streets and park roads, a single-unit truck may be sued 3. at intersections of state highways and city streets that serve buses with relatively few large trucks, a city transit bus may be used.

Question 41

What are the 3 principal elements of a highway cross section?

Answer 41

1. traffic lanes 2. shoulders 3. medians

Question 42

______ include median and roadside barriers, curbs, gutters, guard rails, sidewalks, and side slopes.

Answer 42

marginal elements

Question 43

What are the 7 marginal elements?

Answer 43

1. median 2. roadside barriers 3. curbs 4. gutters 5. guard rails 6. sidewalks 7. side slopes

Question 44

For traffic lanes, on lower trafficked roads, the width can be _____.

Answer 44

reduced

Question 45

For a single lane road traffic, the lane width is ____.

Answer 45

4.0 m

Question 46

For a two-lane national road, the minimum width is ______ (total 6.7 m).

Answer 46

2 x 3.35 m

Question 47

As traffic volume increases, to the need for extra width is justified. This width can increase up to a maximum of _____.

Answer 47

3.65 m

Question 48

The ____ of a pavement cross section is always contiguous with the traffic lane so as to provide an area along the highway for vehicles to stop when necessary.

Answer 48

shoulder

Question 49

_____ is desirable for roads carrying over 1,000 ADT.

Answer 49

paving of shoulder

Question 50

The ____ can accommodate the character of the traffic fleet, the maneuverability of passing needs, emergency parkin, and periodical maintenance of the road.

Answer 50

paved shoulder

Question 51

A ____ is the section of a dividend highway that separates the lanes in opposing directions.

Answer 51

medians

Question 52

Medians can either be ____, ____, or ____.

Answer 52

1. raise 2. flush 3. depressed

Question 53

What are the 7 functions of a median

Answer 53

1. providing a recovery area for out-of-control vehicles 2. separating opposing traffic 3. providing stopping area during emergencies 4. providing storage area for left-turning and U-turning vehicles 5. providing refuge for pedestrians 6. reducing the effect of headlight glare 7. providing temporary lanes and cross-overs during maintenance operations

Question 54

_____ are frequently used in urban arterial streets because they facilitate the control of left-turn at intersections by using part of the median width for left-turn-only lanes.

Answer 54

raised medians

Question 55

What are the 2 disadvantages of raised medians?

Answer 55

1. possible loss of control of the vehicle by the driver if the median is accidentally struck 2. they cast a shadow from oncoming headlights, which results in drivers finding it difficult to see the curb.

Question 56

______ are commonly used on urban arterials.

Answer 56

flush medians

Question 57

Flush medians can also be used on ____,, but with a median barrier.

Answer 57

freeways

Question 58

______ are generally used on freeways and are more effective in draining surface water.

Answer 58

depressed medians

Question 59

A side slope of ____ is suggested for depressed medians, although a slope of ____ may be adequate.

Answer 59

6:1, 4:1

Question 60

A ____ is defined as a longitudinal system used to prevent an errant vehicle from crossing the portion of a divided highway separating the traveled ways for traffic in opposite directions.

Answer 60

median barrier

Question 61

_____ protect vehicles from obstacles or slopes on the roadside.

Answer 61

roadside barriers

Question 62

____ also may be used to shield pedestrians and property from the traffic stream.

Answer 62

roadside barriers

Question 63

_____ are raised structures made of either Portland cement concrete or bituminous concrete (rolled asphalt curbs).

Answer 63

curbs

Question 64

Use mainly on urban highways to delineate pavement edges and pedestrian walkways.

Answer 64

curbs

Question 65

___ also used to control drainage, improve aesthetics, and reduce right of way.

Answer 65

curbs

Question 66

Curbs can be generally classified as either ____ or ____.

Answer 66

1. vertical 2. sloping

Question 67

____ or drainage ditches are usually located on the pavement side of a curb.

Answer 67

gutter

Question 68

To provide the principal drainage facility for the highway.

Answer 68

gutter

Question 69

They are sloped to prevent any hazard to traffic.

Answer 69

gutters

Question 70

Gutters can be design as V-type sections or as ____, ____, ____.

Answer 70

1. broad 2. flat 3. rounded section

Question 71

Pavements on straight sections of two-lane and multilane highways without medians are sloped from the middle downward to both sides of the highway, resulting in a traverse or cross slope, with a cross section shape that can be ___, ___, or____.

Answer 71

1. curved 2. plane 3. combination of the two

Question 72

A parabola is generally used for curved cross sections, and the highest point of the pavement (called the crown) is ____, with the cross slope increasing toward the pavement edge.

Answer 72

slightly rounded

Question 73

____ consists of uniform slopes at both sides of the crown.

Answer 73

plane cross slopes

Question 74

The ____ has once advantage which is that the slope increases outward to the pavement edge, thereby enhancing the flow of surface water away from the pavement.

Answer 74

curved cross section

Question 75

A diadvantage is they are difficult is they are difficult to construct.

Answer 75

curved cross section

Question 76

_____ are provided on embankments and files to provide stability for earthworks.

Answer 76

side slopes

Question 77

The also serve as a safety feature by providing a recovery area for out-of-control vehicles.

Answer 77

side slopes

Question 78

What are the 3 important sections of the cross when being considered as a safety feature?

Answer 78

1. hinge point 2. foreslope 3. toe of the slope

Question 79

The ____ is the total land area acquired for the construction of a highway.

Answer 79

right of way

Question 80

The width should be sufficient to accommodate for all the elements of the highway cross section, any planned widening of the highway, and public-utility facilities that will be installed along the highway.

Answer 80

right of way