Transportation - is defined as the movement of people and goods from one place to another using a variety of vehicles across different infrastructure systems.

Transportation engineering - is the application of technology and scientific principles to the planning, functional design, operation, and management of facilities for any mode of transportation in order to provide for the safe, rapid, comfortable, convenient, economical, and environmentally compatible movement of people and goods.

Transport is divided in 3 types, Land, Sea or Marine, and Air Transport.

Land Transport is consists of Roadways or Highways and Railroads.

Sea or Marine Transport consists of Waterways.

Air Transport then consists of Airways.

In the Philippines, the road infrastructures are managed and monitored by the Department of Public Works and Highways (DPWH). The DPWH is mandated to undertake (a) the planning of infrastructure, such as national roads and bridges, flood control, water resources projects and other public works, and (b) the design, construction, and maintenance of national roads and bridges, and major flood control systems. The Department of Transportation (DOTr), on the other hand, focuses on other modes of transportation such as railway (PNR, MRT, and LRT), airport, and ports (PPA).

Role of Transportations:
Transportation provides a vital part in our daily life as people walk, ride and fly to get to their destination. It is required so people can reach work in time. Several roles of transportation are being classified such as economic, social, political, and environmental (Mathew, 2009)

1. For the economic role of transportation:

   • Building vast transportation systems requires enormous resources of energy, material, and land.

   • Travel is not without danger; every mode of transportation brings to mind some major disaster.

   • Transportation can create noise, spoil the natural beauty of an area, change the environment, pollute air and water, and consume energy resources.

   • Providing medical and other services to rural areas and enabling people to socialize who live some distance apart are just a few examples of the benefits that transportation provides.

2. For the social role of transportation:

   • A person settles from one place to another where the availability of resources is present.

   • The size and pattern of settlements is also considered as the increased speed of transport and reductions in the cost of transport have resulted in variety of spatial patterns.

   • For the growth of urban centers, the development of automobiles, and other factors like increase in personal income, and construction of paved road network, the settlements were transformed into urban centers of intense travel activity.

3. For the political role of transportation:

   • The government of an area must be able to send/get information to/about its people. It may include laws to be followed, security and other needful information needed to generate awareness.

   • For political choices in transport, these choices may be classified as communication, military movement, travel of persons and movement of freight. The primary function of transportation is the transfer of messages and information. It is also needed for rapid movement of troops in case of emergency and finally movement of persons and goods.

4. For the environmental role of transportation:

   • The negative effects of transportation are more dominating than its useful aspects as far as transportation is concerned.

   • The transportation can have an unfortunate on the society in terms of accidents.

   • All transport modes consume energy and the most common source of energy is from the burning of fossil fuels like coal, petrol, diesel, etc. The relation between air pollution and respiratory disease has been demonstrated by various studies and the detrimental effects on the planet earth are widely recognized recently.

   • Sound is acoustical energy released into atmosphere by vibrating or moving bodies whereas noise is unwanted sound produced. Transportation is a major contributor of noise pollution, especially in urban areas.

   • The spectacular growth in industrial and economic growth during the past century has been closely related to an abundant supply of inexpensive energy from fossil fuels. Transportation sector is unbelieved to consume more than half of the petroleum products. The compact of the shortage of fuel was experienced during major wars when strict rationing was imposed in many countries.

   • Sound is acoustical energy released into atmosphere by vibrating or moving bodies whereas noise is unwanted sound produced. Transportation is a major contributor of noise pollution, especially in urban areas.

   • The spectacular growth in industrial and economic growth during the past century has been closely related to an abundant supply of inexpensive energy from fossil fuels. Transportation sector is unbelieved to consume more than half of the petroleum products. The compact of the shortage of fuel was experienced during major wars when strict rationing was imposed in many countries.

IMPORTANCE OF TRANSPORTATION

1. They play an important role in the economic, social and commercial development of the country.

2. They help in cultural development of the country.

3. They help in political development of the country.

4. It plays a vital role in development of rural areas of the country.

5. They improve the employment opportunities.

6. Improves the contact between two countries.

7. Improves the living standard of the country.

8. It helps to improve science and technology.

9. It helps in industrial development throughout the country.

10. Enhances the import and export of the country.

Modes of Transportation

1. Primary Mode

   • Land Transportation

     • Highway: The major advantage of the highway is that it has high accessibility to almost all potential destinations, direct service with very low door-to-door travel times, moderate speeds and capacities. Capital cost for physical facilities is also moderate. Vehicles are small and readily available at a low cost. However, operating cost tends to be higher. Environmental impacts of the system as a whole are high and are a major social concern.

     • Railway: The railway system provides moderate speeds and levels of accessibility. Accessibility is only limited to railway stations. A heavy capital must be invested in both physical facilities and flow entities. This mode is very effective for transportation of a lot of goods through land.

   • Air Transportation: The main advantage of air transport is its high speed and less time consumption. Accessibility is limited but is of less importance as greater lengths of trips are made. Capital investment as well as operating and maintenance cost for both fixed and flow entities are higher than other modes. Environmental impacts are significant, air and noise pollution of commercial aviation but are of less concern than that of highways.

   • Water Transportation: Water transportation provides low speed and relatively low accessibility, but extremely high capacities. The capital cost of vehicles, especially ships are very high but operating cost is low for a large distance. So, if a lot of goods is required for transportation, this mode can be used for best results. Environmental effects are relatively low but the chances of water pollution due to leakage of oil and petroleum products are high.

   • Pipeline Transportation: The transport of daily use products and wastes to the desired location encompass pipeline transportation. They provide very low speed, but the high capacity constant flow and involves a large amount of working storage. Environmental impacts are generally low. Pipeline transport is the long-distance transportation of a liquid or gas through a system of pipes – a pipeline – typically to a market area of consumption.

2. Secondary Mode

   • Cable or Ropeway: is a form of naval lifting device used to transport light stores and equipment across rivers or ravines

   • Unmanned Aircraft: is an aircraft that is operated without the possibility of direct human intervention from within or on the aircraft.

   • Space Flight Transportation: a transportation system which is partially reusable rocket-launched vehicle designed to go into orbit around Earth, to transport people and cargo to and from orbiting spacecraft, and to glide to a runway landing on its return to Earth’s surface.

CHARACTERISTICS OF ROAD TRANSPORT

It is well-know that of all the modes the transportation, road transport is the most convenient one. All passengers and the goods have to be first transported by road before reaching a railway station or a port or an airport. The road network alone could serve the remotest villages and rural places.

The success of transportation engineering depends upon the co-ordination between the three primary elements, namely the vehicles, the roadways, and the road users. Their characteristics affect the performance of the transportation system and the transportation engineer should have fairly good understanding about them. This chapter elaborated salient human, vehicle, and road factors affecting transportation.

1. Human factors: affecting transportation: Road users can be defined as drivers, passengers, pedestrians etc. who use the streets and highways. Together, they form the most complex element of the traffic system - the human element - which differentiates Transportation Engineering from all other engineering fields.

   • Variability

   • Critical characteristics

   • Reaction time (PIEV)

   • Visual acuity and driving

   • Walking

2. Vehicle factors: It is important to know about the vehicle characteristics because we can design road for any vehicle but not for an indefinite one. The road should be such that it should cater to the needs of existing and anticipated vehicles. Some of the vehicle factors that affect transportation is discussed below:

   1. Design vehicles: Road authorities are forced to impose limits on vehicular characteristics mainly:

      • to provide practical limits for road designers to work to,

      • to see that the road space and geometry is available to normal vehicles,

      • to implement traffic control effectively and efficiently,

      • take care of other road users also.

      The vehicular dimensions which can affect the road and traffic design are mainly: width, height, length, rear overhang, and ground clearance.

   2. Turning radius and turning path: The minimum turning radius is dependent on the design and class of the vehicle. The effective width of the vehicle is increased on a turning. This is also important at an intersection, round about, terminals, and parking areas.

   3. Visibility: The visibility of the driver is influenced by the vehicular dimensions. As far as forward visibility is concerned, the dimension of the vehicle and the slope and curvature of wind screens, windscreen wipers, door pillars, etc. should be such that:

      • visibility is clear even in bad weather conditions like fog, ice, and rain;

      • it should not mask the pedestrians, cyclists or other vehicles;

      • during intersection maneuvers.

   4. Braking performance: As far as highway safety is concerned, the braking performance and deceleration characteristics of vehicles are of prime importance. The time and distance taken to stop the vehicle is very important as far as the design of various traffic facilities are concerned. The factors on which the braking distance depend are the type of the road and its condition, the type and condition of tire and type of the braking system.

      Safe stopping sight distance: The minimum stopping sight distance includes both the reaction time and the distance covered in stopping. Thus, the driver should see the obstruction in time to react to the situation and stop the vehicle.

      Clearance and change interval: The Clearance and change intervals are again related to safe stopping distance. All vehicles at a distance further away than one stopping sight distance from the signal when the Yellow is flashed is assumed to be able to stop safely. Such a vehicle which is at a distance equal or greater than the stopping sight distance will have to travel a distance equal to the stopping sight distance plus the width of the street, plus the length of the vehicle. Thus the yellow and all red times should be calculated to accommodate the safe clearance of those vehicles.

      Sign placement: The placement of signs again depends upon the stopping sight distance and reaction time of drivers. The driver should see the sign board from a distance at least equal to or greater than the stopping sight distance.

3. Road factors

   1. Road surface: The type of pavement is determined by the volume and composition of traffic, the availability of materials, and available funds. Some of the factors relating to road surface like road roughness, tire wear, tractive resistance, noise, light reflection, electrostatic properties etc. should be given special attention in the design, construction and maintenance of highways for their safe and economical operation. Unfortunately, it is impossible to build road surface which will provide the best possible performance for all these conditions. For heavy traffic volumes, a smooth riding surface with good all-weather anti skid properties is desirable. The surface should be chosen to retain these qualities so that maintenance cost and interference to traffic operations are kept to a minimum.

   2. Lighting: Illumination is used to illuminate the physical features of the road way and to aid in the driving task. A luminaire is a complete lighting device that distributes light into patterns much as a garden hose nozzle distributes water. Proper distribution of the light flux from luminaires is one of the essential factors in efficient roadway lighting. It is important that roadway lighting be planned on the basis of many traffic information such as night vehicular traffic, pedestrian volumes and accident experience.

   3. Roughness: This is one of the main factors that an engineer should give importance during the design, construction, and maintenance of a highway system. Drivers tend to seek smoother surface when given a choice. On four-lane highways where the texture of the surface of the inner-lane is rougher than that of the outside lane, passing vehicles tend to return to the outside lane after execution of the passing maneuver. Shoulders or even speed change lanes may be deliberately roughened as a means of delineation.

   4. Pavement colors: When the pavements are light colored(for example, cement concrete pavements) there is better visibility during day time whereas during night dark colored pavements like bituminous pavements provide more visibility. Contrasting pavements may be used to indicate preferential use of traffic lanes. A driver tends to follow the same pavement color having driven some distance on a light or dark surface, he expects to remain on a surface of that same color until he arrives a major junction point.

   5. Night visibility: Since most accidents occur at night because of reduced visibility, the traffic designer must strive to improve nighttime visibility in every way he can. An important factor is the amount of light which is reflected by the road surface to the drivers' eyes. Glare caused by the reflection of oncoming vehicles is negligible on a dry pavement but is an important factor when the pavement is wet.

   6. Geometric aspects: The roadway elements such as pavement slope, gradient, right of way etc. affect transportation in various ways. Central portion of the pavement is slightly raised and is sloped to either sides so as to prevent the ponding of water on the road surface. This will deteriorate the riding quality since the pavement will be subjected to many failures like potholes etc. Minimum lane width should be provided to reduce the chances of accidents. Also the speed of the vehicles will be reduced and time consumed to reach the destination will also be more. Right of way width should be properly provided. If the right of way width becomes less, future expansion will become difficult and the development of that area will be adversely affected. One important other road element is the gradient. It reduces the tractive effort of large vehicles. Again the fuel consumption of the vehicles climbing a gradient is more. The other road element that cannot be avoided are curves. Near curves, chances of accidents are more. Speed of the vehicles is also affected.

SCOPE OF HIGHWAY ENGINEERING

• Highway engineering is an engineering discipline which involves the design, construction and maintenance of Highway Roads & Systems, urban streets as well as parking facilities.

• Important aspects of highway engineering include overall planning of routes, financing, environmental impact evaluation, and value engineering to compare alternatives.

• Engineers in this specialization handle the planning, design, construction, and operation of highways, roads, and other vehicular facilities as well as their related pedestrian realms.

  • Estimate the transportation needs of the public and then secure the funding for the project.

  • Analyze locations of high traffic volumes and high collisions for safety and capacity.

  • Use civil engineering principles to improve the transportation system.

  • Utilizes the three design controls which are the drivers, the vehicles, and the roadways themselves.

• The ultimate goal of multimodal transportation networks is to ensure the safe and efficient movement of people and goods on roads and highways. Traffic engineering helps resolve the issues that obstruct that process.

• Beyond the design and construction of transportation infrastructure, traffic engineering focuses on the functional aspects of road geometry that make traffic flow, including traffic signs, signals, intersection management and road surface markings.

• Traffic engineering teams are experienced in research, modeling, planning, auditing and implementing improvements on urban, inter-urban and rural roads. Using engineering and behavioral techniques such as speed management, urban regeneration, streetscaping, multimodal streets and shared space, the said team assist with the following:

  • Traffic calming

  • Traffic signage and markings

  • Traffic signals

  • Roundabouts

  • Variable message signing

  • Pedestrian facilities, management and accommodation in construction areas

  • Bus priority measures

  • Bicycle facilities

  • Traffic signal design and coordination

  • Transportation and traffic outlays

Geometric design - deals with the dimensioning of the elements of highways such as vertical and horizontal curves, cross sections, truck climbing lanes, bicycle paths, and parking facilities.

1. DRIVER CHARACTERISTICS

   • Varying skills and perceptual abilities of drivers on the highway (sight and hearing vary considerably across age groups)

   • Abilities may also vary for individual (alcohol, fatigue, time of day)

   • The characteristics of the driver must be compatible with the criteria for design.

   • Perception-Reaction Process:

     • Perception: control device, warning sign, or object on the road

     • Identification: driver identifies the object & understands the stimulus

     • Emotion: decides on action (brake, change lane etc.)

     • Reaction/volition: driver actually executes the action.

     • Perception-reaction time or PIEV: time elapses during each of these sub processes varies among individuals, vary for same person as the occasion changes.

   • AASHTO specify 2.5 seconds for stopping-sight distance (about 90% of drivers). However, this is not suitable for unexpected or complex conditions such as grade interactions, ramp terminals or when signals are unexpected – reaction time increases by 35%.

2. PEDESTRIAN CHARACTERISTICS

   • Pedestrian is “a person walking rather than travelling in a vehicle”

   • Pedestrian characteristics are relevant to traffic and highway engineering practice because it has influence on design and location of pedestrian control devices.

   • Control devices:

     • Special pedestrian signals

     • Safety zones and islands at intersections

     • Pedestrian underpasses

     • Elevated walkways

     • Pedestrian crossing

   • Characteristics of pedestrian includes visual, hearing, and walking.

   • Walking characteristics play a major part in the design controls.

   • Walking speed vary depend upon the gender and age.

     • Walking speed for male: 1.50 m/s

     • Walking speed for female: 1.41 m/s

     • Walking speed for general design: 1.20 m/s

   • Special considerations should be given to small children, senior citizens, physically handicapped and blind.

     • For blind pedestrian special control devices should be installed for example ring bell signal that conveys to pass on red phase.

     • For handicapped pedestrian ramps are also now being provided at intersection curbs to facilitate the crossing of the intersection by the occupant of a wheelchair.

3. VEHICLE CHARACTERISTICS

4. Criteria for the geometric design of highways are partly based on the static, kinematic, and dynamic characteristics of vehicles.

   • Static characteristics include the weight and size of the vehicle. The size of the design vehicle for a highway is an important factor in the determination of design standards for several physical components of the highway.

     • These include lane width, shoulder width, length and width of parking bays, length of vertical curves.

     • The axle weights of the vehicles expected on the highway are important when pavement depths and maximum grades are being determined.

     • Minimum turning radius

       • Radius of turning circle refers to the distance from the steering center to the contact point of the front and outer steering wheels with the ground when the car is driving. The radius of turning circle when the steering wheel turns to the limit position is the minimum turning radius.

       • Depends on length of wheel base and features of steering system.

   • Kinematic characteristics involve the motion of the vehicle without considering the forces that cause the motion.

     • The primary element among kinematic characteristics is the acceleration capability of the vehicle.

     • Acceleration capability is important in several traffic operations, such as passing maneuvers and gap acceptance.

     • Also, the dimensioning of highway features such as freeway ramps and passing lanes is often governed by acceleration rates.

     • A study of the kinematic characteristics of the vehicle primarily involves a study of how acceleration rates influence the elements of motion, such as velocity and distance.

     • The assumption of constant acceleration has some limitations because the accelerating capability of a vehicle at any time t is related to the speed of the vehicle at that time.

     • The lower the speed, the higher the acceleration rate that can be obtained.

   • Dynamic characteristics involve the forces that cause the motion of the vehicle.

     • Several forces act on a vehicle while it is in motion: air resistance, grade resistance, rolling resistance, and curve resistance. Theses forces including the effect of perception-reaction time are used to determine the braking distance of a vehicle and the minimum radius of a circular curve required for a vehicle traveling around a curve.

     • BRAKING DISTANCE: The braking distance is the distance the car travels from the point at which you begin braking until the car has come to a standstill.

     • MINIMUM RADIUS OF A CIRCULAR CURVE

       • When a vehicle is moving around a circular curve, there is inward radial force acting on the vehicle, usually referred to as the centrifugal force.

       • There is also an outward radial force acting toward the center of curvature as a result of the centripetal acceleration.

       • In order to balance the effect of the centripetal acceleration, the road is inclined towards the center of the curve.

       • The inclination of the roadway toward the center of the curve is known as super elevation.

       • The centripetal acceleration depends on the component of the vehicle’s weight along the inclined surface of the road and the side friction between the tires and road.

5. ROAD CHARACTERISTICS

   • SIGHT DISTANCE

     • Sight Distance is the length of the roadway a driver can see at any particular time.

     • Distance available to a driver ahead of the vehicle on the carriageway that is required for safe operation (i.e., driving) without getting into the hazardous situation such as:

       • Stopping of a vehicle before collision with an object lying or moving on the carriageway ahead

       • Overtaking a vehicle safely

       • Driving safely during night-time

     • Different sight distances are:

       • Stopping Sight Distance

       • Passing Sight Distance

   • STOPPING SIGHT DISTANCE (SSD)

     • The stopping sight distance is the sum of the braking distance and the distance traversed during the brake reaction time. In other words, it is the length of roadway that should be visible ahead of you, in order to ensure that you will be able to stop if there is an object in your path.

     • SSD under different conditions:

       • SSD on a one-lane two-way traffic carriageway is taken as twice the value, as vehicle from opposite direction also move in the same lane.

       • SSD on a two-lane two-way traffic carriageway is taken as single value, as vehicle moves in its own lane.

   • PASSING SIGHT DISTANCE (PSD)

     • Passing Sight Distance (PSD), also called overtaking sight distance, is the minimum sight distance that is required on a highway, generally a two-lane, two-directional one, that will allow a driver to pass another vehicle without colliding with a vehicle in the opposing lane.

     • All vehicles on a road do not travel with the same speed.

     • Drivers intending to move fast will like to overtake the vehicles which are moving at a slower speed.

     • Passing a vehicle will depend upon the suitable condition i.e. the vehicles coming from the opposite direction are at a far away distance and maneuvering from the right of the slow-moving vehicle will not cause an unsafe situation.