Principles of Highway and Railway Planning - Term Paper Example

WEST COAST INSTITUTE OF MANAGEMENT & TECHNOLOGY Bachelor of Science in Civil Engineering ___________________________________ ____ Topic: _______________________________________________ Prepared By Fung Wai Ming____________________ Candidate full name Signature: _______________________________ Date_____________ Candidate signature ENG C247 Land Transportation Engineering Principles of highway and railway planning, design and operations, design of location and route layout, sections and intersections, drainage and earthwork and pavements, finance and economics, construction and maintenance WEST COAST INSTITUTE OF MANAGEMENT & TECHNOLOGY List of contents Page no. 1. Introduction 3 2. Engineering Process 3 3. Planning 3 4. Design 4 5. Operations 5 6. Challenging Aspects 6 7. Finance and Safety 9 8. Future Directions 9 9. Conclusion 10 10. References 10 Principles of highway and railway planning, design and operations Introduction Highways and railways are two of the most ubiquitous land based modes of transportation that are built for social and economic benefits. Highways are main public roads that connect towns and cities, and railways comprise of fixed tracks along which trains run. Although their use, human needs, etc. may change over time and each project is unique, there are some fundamental principles relating to their planning, design and operations, which are briefly explored in this paper. The focus however, is mainly on the transportation engineering side of these phases. In addition, there are general principles, namely coordination, control and routing that apply to all forms of transportation systems and also in ushering future ones (Ghosh & Lee, 2000). Furthermore, the basic concern is always to facilitate the movement of people and goods safely, cost effectively and efficiently. Engineering Process In the overall scheme of the engineering process, planning is the initial stage of the project, design is in the middle, and operation and maintenance takes place after highway or railway construction has been completed. This is roughly a linear process although there is some overlapping in practice. The whole process is illustrated below. Planning The planning stage is intricately tied to urban, suburban and rural planning and also involves making technical forecast decisions and not only socio-economic but also political factors (Gopi). The need for the project is clearly identified and ideally, the community is also involved so that the construction satisfies as many people and needs as possible. In addition, the physical location and surroundings must also be considered carefully during the planning. Detailed planning is also common during major modifications just as much as it is during new constructions or reconstructions. In this case, it could be due to improving capacity, safety, accessibility, structural repairs, etc. Major highways or railways are likely to involve planning at several levels of government and take longer to reach a consensus for its design. The decisions made during the planning stage are so important that they can affect the rest of the entire project and they limit the design options. An important step before beginning on the design is to know exactly what type of highway or railway is to be designed, that is, to know its functional classification, which may even differ in places. With respect to highways, in the U.S the principal classifications are arterial, collector and local. Each differs in regard to the level of service or mobility, design speed, connections and access. The level of service must then match the traffic volume and composition anticipated. In the U.K, the distinction is drawn between motorways, ‘A’ classified roads and local roads. Design The design strategy is a core part of any technical project. It is a creative process that takes the project through three important stages of realization, namely, (1) need, with which all designs begin, (2) vision, from which designs arise as a creative response, and (3) delivery, the result that is a project, system or product which meets the need (RAENG). At the design stage, important considerations are the following: (1) Needs of users, (2) Estimation of construction costs and funding for the project, (3) Sizing, such as width or how many lanes or tracks including ‘clear zones’ (4) Materials, such as type and thickness, (5) Horizontal and vertical alignment (6) Safety issues, etc. These considerations dictate how the design should be. At this stage, there is expected to be “a complete set of plans, specifications, and estimates (PS&Es) of required quantities of materials ready for the solicitation of construction bids and subsequent construction” (FHWA, 2010). Furthermore, by taking into account the surroundings and local values, the information helps to shape “how the project will look and identify any physical constraints or opportunities early in the process” (FHWA, 2010). Integration with the surrounding environment is best achieved by coordinating the horizontal and vertical alignments to blend in and follow permanent natural features of the landscape. CAD tools are especially helpful for this aesthetic purpose. Urban, suburban and rural settings have distinct differences in their physical characteristics. Examples of some specific design considerations are as follows: Locations along the proposed highway/railway that intersect other networks and where pedestrian crossings are required Lines of trees and vegetation along the way and farmlands Areas of special viewpoints along the way or places of historical interest Utility lines along the way such as power lines For example, highways through urban areas will likely require more pedestrian crossings and medians. The latter serve to separate opposing flows of traffic and provide refuge areas among other benefits. Designs that take into consideration all the above are typically very detailed but this is essential and evidence of thorough and careful planning with greater chances of end user satisfaction. The importance of public involvement and wider consultation in such a major project cannot be understated. These also provide opportunities for ideas and changes. Furthermore, by involving the public, it is more likely that certain local area features will become known and community values identified. The most effective way of communicating the design is using visualization tools or models of the proposed highway/railway. Once the design is finalized, a right-of-way usually needs to be acquired for any additional land that the highway or railway has been designed to pass through. Operations The operations side, i.e. after the construction is completed and comes into use, is also a very important phase, which continues throughout the existence of the highway or roadway. It is done in order to maintain it in good working condition. It involves managing the traffic, undertaking repairs and maintenance, and various human factors. Minor changes typically comprise the 3Rs, namely resurfacing, restoration and rehabilitation. Many highway and railway authorities in advanced countries have developed detailed maintenance plans for their highways and railways. As an example, the Torbay council in the UK has detailed its highway maintenance plan in which it states that it strives “to ensure that the network functions efficiently throughout the year” (Torbay Council, 2009). The UK also has a national code of practice for maintaining its highways, which are regarded as highly valuable physical assets both financially and also in terms of the community. In practice, financial constraints limit how much maintenance can actually be carried out. Nonetheless, such plans demonstrate the importance and role of continued work on the highway or railway even after its construction. Challenging aspects Besides the roads and tracks themselves, there are also other associated parts of the whole transportation system that need to be planned for and designed well, especially the pavements and the drainage system. Moreover, as with roads and tracks, it is not only their design but also the materials used in their construction that are important. The main challenging areas of the overall planning involve the following: Site investigation Route planning (including stop locations) Earthwork calculations Design of intersections Design of pavements and sidewalks Design of bridges and tunnels Existence and width of medians, shoulders, curbs, traffic barriers, etc. Channels for drainage Of these, route planning, earthwork calculations, pavements, drainage and intersections will be discussed briefly. The illustration below is another but general perspective of challenges specific to the design phase. Of these, cost and safety will be dealt with in the next section. Major design challenges in highway planning (Adapted from FHWA, 2010) Determining the location and route layout for a new highway or railway is a major initial challenge because of the many complications involved. Most of the land through which the highway or railway is desired to pass is likely to be in use and will need to be acquired. This has social consequences, especially for those who have to be displaced by the project. Then there are environmental considerations and impacts of the chose route as well as cost considerations. There may be places of cultural heritage and geological factors. GIS tools can be useful for determining an appropriate route that balances the social, environmental and economic impact on one hand with the social and economic benefits on the other. For railways in particular, the engineering tasks also include determining the location of stations (Gopi). Stations are an intrinsic part of railway networks and deciding their locations is a strategic decision. Whatever route is finally selected, intersections along the highway or railway are expected, and are critical points that need careful planning. They also determine the characteristics of capacity, speed and especially safety. Intersections can be in the form of a T-junction, four or multi-leg, or roundabouts. According to the AASHTO Green Book (FHWA, 2010), intersections are designed to facilitate “the convenience, ease, and comfort of people traversing the intersections” while minimizing potential conflicts between the various users. There are certain design elements that help to maintain functional use while enhancing safety. These are the use of traffic islands and medians, realignment or closure of intersecting roads, and separation of the turning lanes. It is important that drivers have clear visibility of oncoming traffic from other sections. As for highway-railway intersections, it has long been understood that the safest method is to separate the two levels completely (Goodman & Freund, 1968). Thus bridges, flyovers and underpasses are also solutions for safer intersections. They maximize safety and design speed. Drainage is of paramount importance because excess water or moisture can adversely affect the properties of materials used in the construction (FAO, 1998). Drainage for surface runoff can be accommodated for example in shoulders, which may be either open or closed. Curbs usually serve the same purpose in urban and suburban contexts. Drainage is thus closely associated with pavements. Their structural design and construction, including the materials used and in the case of railways, the rail tracks, comes under the area of Pavement Engineering (Chakroborty & Das, 2004). The materials available heavily influence the design of pavements, which may also change in different locations. However, some general principles do exist. A study of soil mechanics is essential before any work can begin because the ultimate support of pavements derives from the underlying subgrade (Yader & Witczak, 1975). When planning for highways and railways, digital terrain models (DTMs) can help for example in designing routes and making earthwork calculations. These calculations relate to earthwork, such as excavation, fill, riprap, etc. (Choi, 2004). This is necessary because highways and railways span long distances and terrains can vary a lot. Earthwork is minimised by routing through "stable geological conditions, with gentle slopes and small curves" (Li et al., 2005). Both these modes of transportation are likely to require the construction of bridges and tunnels as well. Similarly, modern geotechnical principles are applied nowadays for appraising track and sub-base designs for the purpose of exploring more fundamental approaches and thereby minimise the costs of track maintenance (Rail Research UK). In hilly or mountainous areas, excavations may have to be undertaken of rock cuts. Highways or railways passing through such terrain could have stability issues (Wyllie & Mah, 2004) so extra strength and support is required during its construction, and it will likely require greater maintenance to ensure long-term safety. Finance and Safety The construction of highways and railways are major undertakings, so while quality is important, keeping control of costs at the same time is essential for ensuring feasibility. In addition, safety is also a very important aspect of railway design, as it is also for highways. This should not be an afterthought when breakdowns or accidents occur. Rather, it should be considered at the design and construction stages (An et al., 2002). The highways or railways must then be capable of meeting not only present but also to some extent future anticipated needs. Thus, as part of the planning process, it is also important to take into account expected future requirements. The physical construction aside, there are important economic considerations that dictate what will or will not be possible. In particular, transport economics is concerned with the financial costs and benefits of the entire project, an analysis of cost recovery and obtaining solutions to various transportation problems (Chakroborty & Das, 2004). The real costs and benefits however, would include social and environmental aspects of the project. Thus, along with safety and efficiency and physical aspects, wider challenges in highway and railway planning are to enhance the environment, support community values and enhance the quality of journeys. Future Directions Future transportation systems will need to have the characteristic of intelligence in regard to their operation. This means for example, automated computation, flexibility, accurate information, the use of asynchronous, distributed algorithms for better coordination as opposed to centralised systems, and so on. One such system for railways is DARYN that is based on avoiding collisions and making optimal use of resources (Ghosh & Lee, 2000). Modelling and simulation will play a key role in designing such systems as much as engineering alone does at present. Conclusions This paper has shown that many considerations need to be made for constructing a highway or railway, and it looked in detail at those that arise during the stages of planning, design and operations. Regardless of the type of highway or railway and the location of specific points and the route, the fundamental principles of safety, appropriate routing, and effective coordination and control always apply. In order to ensure this, planning must necessarily be detailed and the design appropriate to meet the actual needs besides promoting aesthetic values. Hence, wide consultation is also important. Specific considerations were shown to pose greater challenges such as designing intersections but the basic principles are still the same. In the end, the overall aim is to enhance the quality of the journey while maintaining harmony with the environment as well. References An, M., Wright, I. C. & Foyer, P. 2002. Design and maintenance for railway safety. Journal of Accident Analysis and Prevention, vol. 34, No. 5. Chakroborty, Partha & Das, Animesh. 2004. Principles of transportation engineering. PHI Learning Pvt. Ltd. Choi, Ying-Kit. 2004. Principles of applied civil engineering design. ASCE Publications. FAO. 1998. Watershed management field manual. Food and Agricultural Organization of the United Nations. United Nations, Publications Division. FHWA. 2010. Overview of the highway planning and development process. U.S. Department of Transportation, Federal Highway Administration. Available at http://www.fhwa.dot.gov/environment/flex/index.htm [Accessed 5 Aug. 2010]. Ghosh, Sumit & Lee, Tony S. 2000. Intelligent transportation systems: new principles and architectures. CRC Press. Goodman, William I. & Freud, Eric C. 1968. Principles and practice of urban planning. Institute for Training in Municipal Administration, International City Managers Association. Gopi, Satheesh. N.d. Basic civil engineering. Pearson Education India. Li, Zhilin; Zhu, Qing & Gold, Chris. 2005. Digital terrain modeling: principles and methodology. CRC Press. Rail Research UK. N.d. Project A1 – Appraisal of track/sub-base design using modern geotechnical principles. Rail Research UK. Available at http://portal.railresearch.org.uk/RRUK/Site%20Pages/Projecta1.aspx [Accessed 5 Aug. 2010]. RAENG. N.d. Design principles: The engineer’s contribution to society. The Royal Academy of Engineering. http://www.raeng.org.uk/education/vps/pdf/design_principles.pdf [Accessed 5 Aug. 2010]. Torbay Council. 2009. Highway maintenance plan. Torbay Council. Available at http://www.torbay.gov.uk/highway_maintenance_plan.pdf [Accessed 5 Aug. 2010]. Wyllie, Duncan C. & Mah, Christopher W. 2004. Rock slope engineering: civil and mining. 4th edition. Taylor & Francis. Yader, E. J. & Witczak, M. W. 1975. Principles of pavement design. 2nd edition. Wiley. Read More