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Unit 1PLANNING AND DESIGN FOR ROADS AND BRIDGESPART 1PLANNING AND DESIGN FOR ROADS1. READINGThe Highway Classification SystemHIGHWAY CLASSIFICATIONSThe classification of highways is necessary for communication among engineers, administrators, and the general public. Different classification schemes have been applied for different purposes in different rural and urban regions. Classification of highways by design types based in the major geometric features (e.g., freeways, conventional streets, and highways) is the most helpful one for highway location and design procedures. Classification by route numbering (e.g., U.S., State, County) is the most helpful for traffic operations. Administrative classification (e.g., National Highway System or NonNational Highway System) is used to denote the levels of government responsible for, and the method of financing, highway facilities. Functional classification, the grouping of highways by the character of service they provide, was developed for transportation planning purposes. Comprehensive transportation planning, an integral part of total economic and social development, uses functional classification as an important planning tool.
PLANNING AND DESIGN FOR ROADS AND BRIDGES Unit PART 1 PLANNING AND DESIGN FOR ROADS READING The Highway Classification System a What you think when you see a new road? Complete the diagram below Safety THE THE ROAD ROAD Speed Landscape Now, compare your diagram with your partners Width b In groups, discuss the different types of classifying highways How many categories are there? What are the purposes of the highway classifications? c Read the first paragraph of Highway Classifications and complete the following table Highway Classification By design types Purpose Examples - is used for highway - freeways, conventional location and design streets, and highways procedures By route numbering Administrative classification Functional classification HIGHWAY CLASSIFICATIONS The classification of highways is necessary for communication among engineers, administrators, and the general public Different classification schemes have been applied for different purposes in different rural and urban regions Classification of highways by design types based in the major geometric features (e.g., freeways, conventional streets, and highways) is the most helpful one for highway location and design procedures Classification by route numbering (e.g., U.S., State, County) is the most helpful for traffic operations Administrative classification (e.g., National Highway System or Non-National Highway System) is used to denote the levels of government responsible for, and the method of financing, highway facilities Functional classification, the grouping of highways by the character of service they provide, was developed for transportation planning purposes Comprehensive transportation planning, an integral part of total economic and social development, uses functional classification as an important planning tool Functional classification is the process by which streets and highways are grouped into classes according to the character of traffic service that they are intended to provide There are three highway functional classifications: arterial, collector, and local roads All streets and highways are grouped into one of these classes, depending on the character of the traffic (i.e., local or long distance) and the degree of land access that they allow These classifications are described in Table Table Functional Classification Systems Functional Services Provided System Arterial provides the highest level of service at the greatest speed for the longest uninterrupted distance, with some degree of access control provides a less highly developed level of service at a lower Collector speed for shorter distances by collecting traffic from local roads and connecting them with arterials consists of all roads not defined as arterials or collectors; Local primarily provides access to land with little or no through movement Typically, travellers will use a combination of arterial, collector, and local roads for their trips Each type of road has a specific purpose or function Some provide land access; others provide travel mobility at varying levels There is a basic relationship between traffic mobility and land access, as illustrated in Figure Mobility Land Access Figure Relationship of functionally classified highway systems in serving traffic mobility and land access Once the functional classification of a particular roadway has been established, the allowable range of design speed, the principal limiting design parameters, and horizontal and vertical alignment have also defined Similarly, functional classification establishes the basic roadway cross section in terms of lane width, shoulder width, type and width of median area, and other major design features (see Figure 2) Figure The flexibility available to a highway designer is considerably limited once a particular functional classification as been established The importance of the functional classification process as it relates to highway design lies in the fact that functional classification decisions are made well before an individual project is selected to move into the design phase Moreover, such decisions are made on a systemwide basis by city or county as part of their continuing long-range transportation planning functions Thus, the functional classification of a particular section of highway may well represent a decision made 10 or more years ago d Match the terms to the definitions Accessibility a provide a balance between mobility and land access Mobility b refers to the ease of reaching destinations Design speed c provide a high level of mobility for through d movement with low level of accessibility provide a high level of access to adjacent properties Arterial roads but a low level of mobility Collector roads e is the ability to move or travel around easily Local roads f is a selected speed used to determine the various geometric features of the roadway Arterial road Collector road Local road e Fill in the blank with suitable words All streets and highways are grouped into one of these classes, depending on the character of the traffic and the degree of that they allow Travellers will use a of arterial, collector, and local roads for their trips Collector roadways provide a balance between and land access provides the highest level of service at the greatest speed for the longest uninterrupted distance A determination of functional classification establishes the basic roadway Functional classification decisions are made as part of their continuing long-range functions f Decide whether the following statements are True (T) or False (F) Arterial, collector and local are grouped into highway functional classifications Traffic mobility and land access don’t have any relationship Local roads provide a high level of access to adjacent properties but a low level of mobility Without defining the allowance range of design speed, horizontal and vertical alignment can’t be defined The functional classification of a particular section of highway may well represent a decision made 10 or more years ago 3 SPEAKING In pairs, describe the figure Relationship of functionally classified highway systems in serving traffic mobility and land access using comparison of adjectives Arterials provide higher mobility than collectors and locals READING AND WRITING Expressways Category a Complete the table with the appropriate descriptions of Functional Classification A Highways generally providing direct service between cities and important economic, political, cultural centres; Partial Controlled Access Highways; ≥4 lanes B Local Roads providing direct service between districts, cooperatives, etc C Super high class Highway for high speed traffic with controlled access and quick travel time, providing transport service between large important cities D Highways providing direct service between several towns and local economic, political, cultural centres Roads connecting them to the arterial network and expressways E Highways providing direct service between big economic, political, cultural centres; Road connecting them to the Ind category or expressways – lanes Traffic Volume PCU/day Technical Classification Functional Classification Level Administrati ve Rollin Mountainou Classificatio g s n 120 100 National Road 80 80 60 100 >25000 ≥ 15000 110 100 90 80 70 60 National Road I II ≥6000 100 80 80 60 60 40 National Road 60 40 50 30 National or ≥1000 80 60 III Provincial Road 60 40 ≤2001 lane > 200- IV 40 30 30 20 Local Road lanes b Translate the above table into Vietnamese Grammar focus: Zero relative clause (Omitting relative pronouns) E.g Arterials are the highways providing the highest mobility (understood: Arterials are the highways which provide the highest mobility) HIGHWAY CROSS-SECTION ELEMENTS VOCABULARY BUILDING Property Lines a Guess the meaning of the following terms Clearing Limits Right-of-Way Clearing Limits Roadway (Construction Limits) Traveled Way Shoulder Shoulder Cut Slope (Back Slope) C L Surface Course Base Course Fill Slope Subgrade (Embankment) Ditch Road bed Toe of Slope Property Lines Clearing Limits Natural Ground b Label the following cross-section elements MEDIAN Cross-section Elements for a Divided Highway Information sign Median Sound/Noise barrier Flexible Curb Roadway Railing/Wall barrier Shoulder Shoulder (Inner) Traveledway Pavement railing (Outer) LISTENING a What is a safe highway? How can we design a safe highway? b Watch a video and choose the best answer (A, B, C, or D) for the following sentences will be a new arterial highway for Japan A Expressway B New Tomei C This Expressway D New Tomei We aim to make this the world’s safest, most pleasant expressway coexisting harmoniously with A environment B natural C nature D feature We are engaged in a wide range of measures to accidents on expressways A maximize B optimize C customize D minimize We have widened the road, reduced and so decreased driver stress and improved road visibility A curves and bends B curves and slopes C slopes D curves We have made traffic signs and much easier to read by improving the colors and shapes based on intensive testing A signboards B signboard C side roads D side road The expressway is paved with paving material A traditional B modern C advanced conventional D The expressway has been planned and designed anticipating a possible A tsunami B typhoon C earthwork D earthquake In addition to being light and pleasant to drive through, we have employed lighting consuming less power than conventional lights A eco-friendly environment-friendly B ecosystem C economic D We use advanced systems with TV cameras to monitor the entire expressway A supervising B monitoring C inspecting D observing c Watch again for more information What have they done to make New Tomei Expressway the world’s safest, most pleasant expressway? SPEAKING HORIZONTAL AND VERTICAL ALIGNMENT Horizontal and vertical alignments are permanent elements that should not be designed independently They complement each other, and poorly designed combinations can spoil the good points and aggravate the deficiencies of each Working drawings, with the profile plotted jointly with the plan, assist in analyzing the horizontal alignment and profile relationship in roadway design Indicate in the following figures whether the layout is a good or poor highway design practice by checking the appropriate box Useful expressions: I think so I don’t think Probably I’m sure As you can see Because Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice Good design practice Poor design practice