COLUMBIA INSTITUTE ENGINEEERING AND TECHNOLOGY.pdf

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COLUMBIA INSTITUTE OF ENGINEERING AND TECHNOLOGY ,RAIPUR

TRANSPORTATION ENGINEERING –II LAB MANUAL

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List of experiments :- PAGE-NO

I) Marshal stability test for Bituminous concrete. (3-5) II) Study of joints in rigid pavement. (6-8) III) Study of Origin and Destination survey (9-13) IV) Study of signal design. (14-20) V) Study of parking design. (21-25) VI) Study of speed volume data (30th peak hourly volume). (26-30)

VII) Study of signaling and interlocking of railway tracks. (31-33) VIII) Study of points and crossing (34-36)

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Columbia Institute of Engineering and Technology, Raipur.

Department of Civil Engineering.

Transportation Engineering –II Lab Manual………..

Experiment No:-1

Aim: - Marshal stability test for Bituminous concrete.

Apparatus: - a) marshal stability apparatus b) Water bath and balance. Theory: - The sample needed is From Marshall stability graph, select proportions of coarse aggregates, fine aggregates and filler in such a way, so as to fulfill the required specification. The total weight of the mix should be 1200g.

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Procedure:-

i) Heat the weighed aggregates and the bitumen separately up to 170oC and 163oC respectively. ii) Mix them thoroughly, transfer the mixed material to the compaction mould arranged on the compaction pedestal.

iii) Give 75 blows on the top side of the specimen mix with a standard hammer (45cm, 4.86kg). Reverse the specimen and give 75 blows again. Take the mould with the specimen and cool it for a few minutes.

iv) Remove the specimen from the mould by gentle pushing. Mark the specimen and cure it at room temperature, overnight.

v) A series of specimens are prepared by a similar method with varying quantities of bitumen content, with an increment of 0.5% (3 specimens) or 1 bitumen content.

vi) Before testing of the mould, keep the moulds in the water bath having a temperature of 60oC for half an hour. vii) Check the stability of the mould on the Marshall Stability apparatus.

Result: - Plot % of bitumen content on the X-axis and stability in kg on the Y-axis to get maximum Marshall stability of the bitumen mix. A sample plot is given

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Experiment No:-2

Aim: - Study of joints in rigid pavement.

Theory:-

Joints are provided in cement concrete roads for expansion, contraction and warping of the slabs due to the variation in the temperature of slabs.

These are classified into two types i) Transverse joints

ii) Longitudinal joints

i) Transverse joints:- these are further classified as a) Expansion joint

b) Contraction joint

c) Warping joint

d) Construction joint

a) Expansion joint: - these joints are provided to allow for expansion of the slabs due to rise in slab temperature above the construction temperature of the cement concrete. Expansion joints in India are provided at interval of 50 to 60 m for smooth interface laid in winter and 901 to 120m for summer.

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b) contraction joint: - These are provided to permit the contraction of the slab .As per IRC specifications the maximum spacing of contraction joints in unreinforced cc slabs is 4.5 m and in reinforced slab of thickness 20 cm is 14 m.

c) Warping joint: - these types of joints are provided to relieve stresses included due to warping .These are known as hinged joints.

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ii) Longitudinal joints :-

These are provided in cement concrete roads which have width over 4.5 m. on soil sub grade of clay, such joints are provided to allow differential shrinkage and swelling due to rapid changes in sub grade moisture under the edges than under the center of the road.

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Experiment No:-3

Aim: - Study of Origin and Destination survey.

Theory: -

An origin-destination study is used to determine travel patterns of traffic on an installation during a typical day. They are useful in assisting long-range traffic planning, especially when there are substantial changes anticipated in the installation mission or strength.

This is a study to determine and analyze trips. Trips are defined as one-way movement, from where a person starts (origin) to where the person is going (destination). Trips are further classified as follows:

Internal--From one point on post to another point on post.

External--From on-post to off-post or vice versa.

Through--From off-post to off-post, by going through the installation.

Procedure:-

Conducting Studies

There are five methods which can be used in conducting these studies; so this decision must be made before planning can be completed.

Planning

The number of personnel needed to conduct this study depends on the method of study used.

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A sampling of the person's driving (or making trips) will be taken. This sample is then multiplied to represent the total population. Because of this, a true representation of drivers must be made. The greater the number of samples, the more accurate the study will be.

Motorists should be made aware in advance of the reasons for the study. Information concerning the study should be disseminated to the public.

There are five methods by which an origin-destination study can be made. These are:

1. Registration Questionnaire--Driver lists are obtained from the vehicle registration form and each is sent a questionnaire at his place of duty with a return date requested.

2. Post Card--A prepaid post card with the questionnaire on it is distributed to all drivers entering the installation during a given time. A traffic volume count is made at the time the cards are distributed.

3. Roadside Interview--This method requires advance publicity and a greater number of personnel. Uniformed MPs should conduct the interview. Considerations should include:

Interview 50 percent of vehicles during non peak hours.

Interview 25 percent of drivers during peak hours.

Insure stations are visible and safe. One interview should not take more than 40 seconds, and there should not be more than five (5) interviewers in a file (one lane).

Approximately 300 drivers can be interviewed per hour. Stations do not have to be operated at the same time.

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A manual count of traffic is made by hour, direction and type of vehicle. By doing this the sample can be expanded into a 24-hour analysis.

4. Tag on Car--This is a limited study good for studying through trips. It is conducted by having all cars counted when they enter the installation. At stations just inside the entrance gates, MPs stop vehicles and affix a piece of colored tape (different for each station) to the car's front bumper. At exit gates of the installation, a tally of cars with each colored tape is made. It provides a rough estimate of through trips on the installation. It's necessary for each installation entrance and exit to be manned during this study.

5. Comprehensive Home Interview--This method is performed by other governmental organizations. It is not normally done on a military installation unless it is near a large city that is under review. It provides the most detailed data.

The guide to origin destination studies table can be helpful in choosing the best method for your studies.

Origin-destination studies may be augmented with the following studies:

Land Use Study--This study of an installation and the surrounding area concerns residential, industrial, commercial and recreational land use. See AR 210-20 for more information.

Growth Trends Study--This study concerns trends in population, land use and highway travel. It is made in conjunction with planning agencies, utility companies and highway officials. Population trends are classified as military/civilian office workers, civilian maintenance, contractors, hospital personnel, service personnel and visitors.

Off-Post Route Improvements--Studies of new routes or changes in routes off post by local officials should be considered.

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Graphics

There are several methods to graphically portray information obtained from these studies. Two examples are the line desire map and the route volume map. In the line desire map, each dark line or bar, of varying widths, represents traffic volume from one key area to another. The line desire map locates pictorially the major traffic patterns.

Another method of showing this information is by bars signifying volume superimposed on an actual road map. This is a route volume map.

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Experiment No:-4

Aim: - Study of signal design.

Theory:-

Standard References for Traffic Signals:-

The following are standard reference documents for the design of traffic signals.

1. For new or upgraded signal installations, the number of signal indications and their location should conform to requirements in Part IV of the Manual on Uniform Traffic Control Devices (MUTCD). 2. Equipment, materials and installation procedures should meet or exceed the 1994 Pima County/City of Tucson Standard Specifications for Public Improvements, and 1994 Pima County/City of Tucson Standard Details for Public Improvements, unless noted otherwise in the construction documents, or superseded by direction in this manual. 3. All installations should meet National Electric Code requirements. 4. Steel pole, control cabinet, and electric service pedestal foundations should be positioned beyond the clear zone requirements, whenever possible, as specified in the 1996 AASHTO Roadside Design Guide (convert to English measurements). 5. Plans should conform to the City of Tucson, Department of Transportation, Engineering Division, Active Practice Guidelines, Office Procedure No. 8-1552- 002, Rev. No. 1, 9/12/00.

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Standard References for Street Lighting at Signalized Intersections. While this manual is not intended to be a street lighting design manual, intersection lighting is included in traffic signal designs. For this reason, standard references for intersection lighting are specified. 1. Street lighting design should meet or exceed average illuminance per the AASHTO publication, An Informational Guide for Roadway Lighting, 1984. 2. Pole locations should be positioned beyond the AASHTO clear zone requirement, whenever possible, as specified in the AASHTO Roadside Design Guide, 1996 (convert to English measurements).

Related Studies 1. Traffic Signal Warrant Analysis At the start of the design process, COT/DOT/TED will provide information on the type of control traffic to be used for intersections. However, the designer may on occasion be asked to prepare a warrant study for new signal installations. The warrants as found in the MUTCD are used for making such a study. There are 8 warrants which relate to the volume, delay, and accident experience of the intersection. Satisfying one or more of these warrants may be an indication that installation of traffic signals is appropriate. 2. Left-Turn Warrant Study A left turn warrant study using City of Tucson criteria is typically completed by COT/DOT/TED for the existing year volumes prior to the traffic signal design, when necessary. 3. Traffic Signal and Lighting Report A Traffic Signal and Lighting Report may be required under certain circumstances. 4. Project Traffic Engineering Report For many roadway civil designs, a project Traffic Engineering Report may have been completed. This report presents existing and future conditions and discusses proposed improvements. The report also includes information about proposed traffic signal operation and phasing.

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POLE PLACEMENT STANDARDS AND GUIDELINES

A. Curb Access Ramp Locations

Curb access ramps are required by the Americans with Disabilities Act (ADA). These ramps should be provided via two separate ramps per corner, one for each crossing direction. Special circumstances may require the use of single joint ramps, which requires the pre-approval of the COT/DOT/TED Project Manager. B. Curb Access Ramp Landings A curb access ramp landing is a relatively flat area to be used by a pedestrian to access and activate a pedestrian push button. A landing should be provided at the top of each curb access ramp. The landing should contain a 60-inch square or 60-inch circle, and should slope no more than 1:48 in any direction, in accordance with the Final Report of the Public Rights-of-Way Access Advisory Committee (January 2001). The landing should be provided with a stable, firm, and slip resistant surface. Poles, utility boxes, and other obstructions shall not be located in the curb access ramps or in the landings. C. Relationship of Curb Access Ramps with Crosswalks and Stop Lines The location of the curb access ramps determines the location of the marked crosswalks and associated stop lines. The stop lines determine the placement of the detection loops and any “near right” poles. Therefore, the design/location of any of these features must be coordinated with the design of the other features. Listed below are design/operation factors to be balanced in the location of curb access ramps, crosswalks, and stop lines: 1. Align crosswalks and stop lines as close to perpendicular to the approach traffic lanes as possible. 2. Center the curb access ramps in the crosswalks. 3. Locate curb access ramps near the radius PT and PC. 4. Minimize pedestrian exposure to turning vehicles. 5. Ensure that the pedestrians waiting at the radius, at both curb access ramps, are readily visible to approaching and turning vehicle drivers.

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6. Minimize pedestrian crossing distance and crossing time. 7. Clarify and simplify the pedestrians crossing route.

General Considerations For Traffic Signal Pole Locations:- Traffic signal poles should be located to provide for the best visibility of signal face by balancing the following design issues. 1. Accommodate right-of-way limitations. 2. Locate signal heads (vehicle and pedestrian heads) to maximize visibility and minimize confusion. 3. Accommodate approach lane configuration. 4. Accommodate alignment of intersecting roadways (skew intersections). 5. Accommodate approach alignment (horizontal and vertical curves). 6. Minimize the number of poles for signal heads, pedestrian buttons, and street lighting. 7. Provide street lights in reasonable locations. 8. Account for nearby underground and overhead utilities (existing/proposed). 9. Account for nearby drainage structures, bridges and embankments. 10. Account for nearby buildings, walls, fences, and other structures. 11. Account for the corner radius. 12. Determine reasonable curb access ramp locations. 13. Enhance access to pedestrian push buttons. 14. Account for nearby trees and other landscaping features. 15. Use standard mast-arm lengths.

TRAFFIC SIGNAL FACES AND MOUNTING HARDWARE A. Traffic Signal Indications 1. All signal lenses shall be 8-inch or 12-inch diameter and in conformance to the MUTCD Section 4D.15. 2. All traffic signal indications should utilize light emitting diodes (LEDs) as the light source, with the exception of the yellow circular indication, which should be an incandescent lamp. All arrow and pedestrian indications shall be LED. B. Traffic Signal Faces 1. Typical traffic signal faces should be yellow polycarbonate. The traffic signals at signalized intersections shall be Type C, F, H, Q, INV J, or as illustrated in MUTCD Figure 4D-3 (o), which should be used for span-wire installations. All signal faces should have black aluminum louvered back plates.

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2. Optically programmed or louvered heads may be used if the physical geometry or operational problems indicate their use. The COT/DOT/TED Project Manager must approve the use of optically programmed or louvered heads. 3. Left turn signal faces shall be Type H or Q, or MUTCD Figure 4D-3 (o). 4. Right turn signal faces shall be Type H or Q and will generally have a flashing right yellow arrow instead of a green arrow. 5. Type D and E signal faces shall be used as flashing beacons (see Section 11). 6. See Figure 3-1 for HAWK signal head layout. Traffic signal faces are shown in Standard Detail T.S. 8-1 of the Pima County/City of Tucson Standard Details for Public Improvements. C. Placement Considerations For Traffic Signal Faces Placement of traffic signal faces will consider the following: 1. The requirements of MUTCD Sections 4D.15, 4D.16, and 4D.17 shall be satisfied. 2. Minimum spacing of traffic signal faces should be 12 feet unless otherwise requested. 3. Traffic signal faces for one direction of travel should not obstruct the visibility of signal faces for the opposing direction of travel. 4. Install one overhead signal face on 30’ mast arms, two on longer mast arms. Use a minimum of one overhead face per approach. 5. Provide a far left indication at locations not having median island poles. 6. Provide two or three faces for left turn lanes, as discussed below: a. Single left-turn lane – Provide one overhead face positioned over or near the right edge of the double yellow line. Provide a second face on the far left corner on a Type A pole or street light pole near the stop line for opposing traffic. For locations having islands, signals shall be on the near and far side islands. b. Dual left-turn lane – Provide one overhead signal face aligned with or near the line separating the left turn lanes. Provide a second signal face on the far left corner, as discussed in item a, above. For locations having islands, replace the overhead signal face with a signal face mounted on a Type A pole in the medians as discussed in item a, above. Provide a third signal face on the far left corner. 7. Provide two signal faces for right-turn lanes having right-turn signal phasing, as detailed below: a. Provide a far side mounted signal face. b. Provide a near right signal face on a Type A pole or street light pole near the stop line.

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c. Right turn signals will generally have a flashing right yellow arrow instead of a green arrow. 8. Use prohibited/protected left turn phasing (Type H or Q face) unless otherwise directed by COT/DOT/TED 9. Additional signal faces may be needed when the view of the normal signal faces are concealed from approaching drivers due to horizontal or vertical alignment. Refer to Figures 2-2 through 2-12 for sample drawings illustrating common intersection and signal configurations. PEDESTRIAN CONTROL FEATURES As with curb-access ramps, pedestrian control features need to meet accessibility standards. A. Conventional Pedestrian Signals 1. Conventional pedestrian signals are typically utilized for all legs of all intersections. There may be occasions where some legs of some intersections will be without crosswalks. These will be intersection and project specific. 2. Pedestrian signals will be of the conventional type, as depicted in the Pima County/City of Tucson Standard Details for Public Improvements, unless otherwise approved by the COT/DOT/TED Project Manager. B. Accessible Pedestrian Signals 1. Accessible Pedestrian Signals are described in detail in the MUTCD Section 4E.06. Accessible pedestrian signals communicate information about pedestrian signal timing in a non-visual format, through the use of audible tones (or verbal messages) and vibrating surfaces. 2. Upon request for an accessible signal for a particular location, COT/DOT/TED will conduct an engineering study that considers the safety and effectiveness for pedestrians in general, as well as the information needs of pedestrians with visual disabilities. Accessible pedestrian signals should conform with MUTCD Section 4E.06. C. Pedestrian Signal Indications and Push Buttons 1. Pedestrian signal indications should utilize light emitting diodes (LEDs). 2. The pedestrian push button shall be a 2-inch stainless steel ADA button. D. Placement Considerations for Pedestrian Signal Heads and Detectors 1. Mount the pedestrian push button adjacent to the landing on the sidewalk area leading to the crosswalk. 2. Mount the pedestrian push button no further than 5 feet from the extension of

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the crosswalk lines and within 10 feet of the curb line, unless the curb ramp is longer than 10 feet. 3. For two pedestrian push button stations on the same corner, mount the pedestrian push buttons on poles or posts separated by at least 10 feet, whenever possible.

LIGHTING REQUIREMENTS FOR TRAFFIC SIGNAL INSTALLATIONS COT/DOT/TED may require advance intersection street lighting. Intersection lighting is included at signalized intersections. The following are considerations for intersection street lighting. A. Considerations for Intersection Lighting 1. Illuminate each approach. At a minimum, utilize one luminary for each leg of the intersection. Wider streets, higher volumes and/or urban conditions may require two fixtures per leg. 2. Location of luminary’s poles should meet guidance contained in Chapter 2 of this document. 3. Light distribution should conform to Pima County Outdoor Lighting Code, October 16, 2001. 4. All installations should meet National Electric Code requirements. 5. Roadway Lighting – Illuminating Engineering Society of North America, ANSI/IESNA RP-8, 2000 provides guidelines that can be used by the designer upon approval of the COT/DOT/TED Project Manager. B. Lighting Requirements for Traffic Signal Installations 1. Intersection lighting shall use 120 volt, 400 watt high pressure sodium luminaries with horizontal cut-off lenses meeting Pima County/City of Tucson specifications. Use of other wattage and voltage requires prior approval from the COT/DOT/TED Project Manager. 2. The street lighting photo electric cell shall be mounted on the luminaries on the pole closest to the traffic signal controller cabinet. 3. For corners with dual luminaries, provide alternating separate circuits for each luminary.

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Experiment No:-5

Aim: - Study of parking design.

Theory:- Parking areas are an important component of many transportation facilities such as safety rest areas, park and ride lots, and viewpoints. The parking area is often the first thing users see upon entering the facility, creating an important first impression. The optimum design for a parking area is not necessarily one that provides the maximum number of parking spaces. It is one that provides safe pedestrian and vehicular circulation, with ample stall and aisle widths, adequate turning radii, reasonable gradients, a pleasing appearance, visual access for law enforcement surveillance, provisions for handling and treating storm water runoff, fits the site, is easy to maintain, and is in close proximity to the facility it serves. These elements illustrate the complexity of issues that must be addressed in parking area design. Studies show that the use of shaded parking in hot weather can reduce noxious emissions by up to a ton a day for a municipality. The use of porous pavements for overflow parking areas can decrease the size of storm water facilities needed.

Procedure:-

Definitions context sensitive design A collaborative, interdisciplinary approach that involves all stakeholders to develop a transportation facility that fits its physical setting and preserves scenic, aesthetic, historic, and environmental resources, while maintaining safety and mobility. Context Sensitive Design is an approach that considers the total context within which a transportation improvement project will exist.1 facility All or any portion of buildings, structures, vehicles, equipment,

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roads, walks, parking lots, or other real or personal property or interesting such property. Planning:- When choosing locations for parking facilities consider impacts the facility will have on existing desirable vegetation, topography, and adjacent neighbors. For example if there are large trees, how can parking be sited to preserve these trees? How can the site design minimize grading? Encourage design and placement of facilities to provide for safety and access to services by many different types of transportation, such as car, bicycle, or pedestrian travel. Location of the parking facility in relation to the facility it serves should be carefully considered. Parking areas should not be the dominant visual element of the facility. Rather, the parking area design should direct the viewer to the main point of entry or attention. Design:- Adjust design to comply with local regulations and requirements. Design aisles and breaks in planting strips to provide for easy maintenance.

Aisles should be wide enough to allow access street sweepers. High points in corner areas will allow water to drain away from these locations so they do not collect water and leaves. Refer to planting area design later in this chapter for additional design considerations. Ensure environmental quality by addressing air, drinking water and noise

concerns, watershed restoration, and preservation of habitats and public green spaces. Use transportation facilities to enhance community aesthetics by incorporating

unique local features (scenic views, community neighborhoods, historic districts, cultural and natural resources, etc.)and providing focal points for communities

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through those facilities such as multimodal stations, pedestrian plazas, and parkways. Pedestrian Safety Security:- Users of a facility should feel safe and not feel imprisoned or threatened. For example lighting, security cameras, emergency telephones, and appropriate vendors are preferable to fences and on-site security. Frequent removal of graffiti, broken glass, and trash is important when providing an environment that feels safe and secure to the user.3 The perception of safety is as important as its reality. In planting areas near conflicting traffic movement, such as backing vehicles or opposing traffic, select shrubs and groundcovers that grow no higher than 2 feet and keep trees limbed up to 8 feet above ground level to provide clear sight lines for safe traffic movement.4 Clear lines of vision are important so that police can provide surveillance within the site and surveillance from the street. Lighting is an important component in pedestrian and vehicle security and safety. Sidewalks:- Provide sidewalks near bus transfer areas or a scenic viewpoint with a minimum width of 10 feet. Provide 10 square feet per person for each user expected to be at the focal point at any one time: Accessibility:- All pedestrian facilities must be designed to meet standards set by the Americans with Disabilities Act. See Chapter 620 of this manual for these guidelines. Accessible parking spaces must be located nearest to the destination point, such as a rest room or bus stop. The number of accessible parking spaces shall be provided according to Figure 630.16:

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Lighting • Consider adjacent land uses when designing the illumination plan. Using trees and tall shrubs to screen the parking facility’s vehicle activity and lighting from adjoining residential land use can be effective and may be required by county or local code in many locations. • Pay particular attention to the scale of lighting fixtures in pedestrian areas. Standard heights for roadway lighting are not appropriate for pedestrians. • Ensure that lighting illuminates pedestrian pathways, not just the roadway. • Lighting maintenance requires set-up room for the man-lift truck to change lights. Replacement of lights can occur during midday or off peak hours, but must be taken into consideration during the design of the facility. • Junction boxes and hand-hole access at the poles must be accessible for servicing and not covered with vegetation.

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Pedestrian Circulation:- Clear separation of pedestrian and vehicle circulation will increase safety in parking facilities. Once people leave their vehicles, lines of approach to the bus stop or toilets should be obvious. People will take the shortest, most direct route to their destination. For park and ride lots, aisle lengths should not exceed 400 feet if possible.9 Minimize pedestrian crossings in front of moving vehicles. When this is necessary, especially in safety rest areas, provide clues to the drivers before pedestrian crossings. Cues can include items such as: • signing • painted crosswalks • rumble strips in advance of a stopping or slowing condition • speed bumps • raised crosswalks • embedded lights in pavement Parking areas may require more aggressive delineation than typical roadway applications to indicate pedestrian paths and vehicular channelization. Using planting islands to direct pedestrian an vehicular traffic can be effective. Vehicular Circulation:- Separate vehicle circulation from pedestrian circulation as much as possible. In two-way vehicular circulation patterns, minimize left hand turns when entering the lot to minimize traffic delays. The most desirable direction for internal circulation within the parking area is clockwise. This is because it follows the normal pattern of driving to the right. Locate the vehicle entrance and exit far from the major pedestrian circulation area. For example, locate the entrances as far from the bus stop as possible

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. Columbia Institute of Engineering and Technology, Raipur.



Experiment No:-6 Aim:- Study of speed volume data (30th peak hourly volume).

Theory :-

Volume --- is defined as the number of vehicles (or persons) that pass a point on a transportation facility during a specified time period, which is usually one hour or one hour, but need not be. In traffic engineering studies there are many volumes such as daily volume, hourly volume, peak hour volume. In addition volumes of a day or an hour can vary greatly, depending on the different day of the week or different time period of a day.

� AADT (Average Annual Daily) --- average of 24-hour traffic volume at a given location over a full 365-day year

� AAWT (Average Annual Weekday Traffic) --- average 24-hour traffic

volume occurring on weekdays over a full year, AAWT is computed by dividing the total weekday volume for the whole year by 260.

� ADT (Average Daily Traffic) --- average 24-hour volume at a given

location for some period of time less than a year.

� AWT (Average Weekday Traffic) --- average 24-hour traffic volume occurring on weekdays for some period less than one year.

The relationship between AAWT and AWT is analogous to that between

AADT and ADT. It should be mentioned here that these four volumes are often used in transportation planning and shown in social or economic statistics.

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� Daily variation factor (DF) --- is defined as ratio of AADT over yearly average volume for particular day of week (Monday, Tuesday etc.)

� Monthly variation factor (MF) --- is defined as ratio of AADT over ADT for particular month of the year.

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Daily variation factor and monthly variation factor are used to reflect the fluctuation of average daily traffic over a day or a month. If values of DF and MF are greater than 1.0 it indicates that average daily traffic for this day or month is lower than AADT. If values of DF and MF are less than 1.0 it indicates that average daily traffic for this day or month is higher than AADT.

From engineering design point of view hourly volumes are more often used. � Hourly volumes and peak hour volume --- Hourly volumes are used to

reflect variation (fluctuation) of traffic volume in a day and peak hour volume is defined as the volume in the single hour that has the highest hourly volume. Sometimes, peak hour is also called rush hour.

� Rate of flow --- defined as an equivalent hourly volume for a given interval

(interval can be 5, 10, 15 minutes) .

Assuming V5, V

10, and V

15 representing rate of flow for 5, 10, and 15 minutes

intervals, so we have twelve rates of flow for 5-minute interval, six rates of flow for

10-minute interval, and four rates of flow for 15-minute interval: V

5 = (180, 300, 216, 504, 372, 216, 204, 420, 336, 384, 312, 240)

V10

=(240, 360, 294, 312, 360, 276) V

15=(232, 364, 320, 312)

Thus: Max V

5 = 504; Max V

10 = 360; Max V

15 = 364

It is widely accepted that 15-minute interval is considered the standard time period used, primarily based on the belief that this is the shortest period of time over which flow rates are “statistically stable”.

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Peak hour factor:-

It used to reflect the stability of volume distribution in an hour. Peak hour

factor (PHF) is defined as the ratio of hourly volume divided by maximum rate of flow.

PHF = hourly volume/maximum rate of flow For the above case we have: PHF

5 = 307/504 = 0.61;

PHF10

= 307/360 = 0.85;

PHF15

= 307/364 = 0.84;

Two features of PHF: (1) 0<PHF<1 (2) the less the value of PHF, the more the fluctuation of the traffic flow within an hour

In general PHF is used to reflect the evenness of peak-hourly flow. If the value of PHF is very small it shows that the coming traffic flow during peak hour is not evenly distributed. If the value of PHF is close to 1.0 it indicates that the coming traffic flow is evenly distributed.

� The 30th

hourly volume (第30位小时交通量 )--- defined as an hourly

volume at which its ranking on yearly-counting curve counts 30th

among 8760 hourly volumes in a year. The value of this point is considered in the planning and design of roadway facilities because the volume-ranking curve begins to “flatten out” after this point.

� The 30th

highest hourly volume --- defined as an hourly volume at which its

ranking on yearly-counting curve counts 30th

among 365 peak hour volumes in a year. This volume is not often used in practice.

� DDHV --- （directional design hour） DDHV = AADTK D where: K is proportion of daily traffic occurring during ⅹ

� The peak hour, expressed as a decimal; D is proportion of peak-hour traffic traveling in the peak direction, expressed as a decimal.

� VMT (Vehicle Miles Traveled) or VKT(Vehicle Kilometers Traveled) --- another parameter to estimate product of volume and average travel length

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for a trip. This element is often used as an important statistics to measure intensity of vehicles using roadways.

Passenger Car Unit ( PCU):-

� PCU (or PCE) --- Passenger Car Unit (Passenger Car Equivalent) is defined

as the number of passenger cars displaced by one truck, bus, or RV (recreational vehicle) in a given traffic stream. In order to reflect the different impact or intensity on the roadway due to the different vehicles in terms of size, operating characteristics, passenger car unit (passenger car equivalent) is applied in the estimation of traffic volume. (see Tables 12.14, 12.15, 12.16 page 311-312)

� More roadway space for heavy vehicles than passenger car � Heavy vehicles include truck, buses and recreational vehicle � The more the grade, the higher the PCE values � The higher the percent of heavy vehicles, the less the PCE values

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Experiment No:-7

Aim: - Study of signaling and interlocking of railway tracks.

Theory:-

Objects of signaling:-

a) To provide facilities for the efficient movement of trains. b) To ensure safety between two or more trains which cross each other’s path? c) To provide facilities for the maximum utility of the track. d) To guide the trains movement during maintenance and the repairs of the track.

Classification of signaling:-

These are classified into four types

a) Operating characteristics b) Functional characteristics c) Locational characteristics d) Special characteristics

a) Operating characteristics :- again it can be classified into three types i) Detonating signals ii) Hand signals iii) Fixed signals

b) Functional characteristics:- again it can be classified into four types i) Stop or semaphore type signals ii) Warner signals iii) Shunting signals iv) Colored –light signal

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c) Locational characteristics:- again it can be classified into two types i) Reception signals

a) Quoter signal b) home signal ii) Departure signals

a) Starter b) advance starter d) Special characteristics:- again it can be classified into six types

i) Repeater or co-acting signals ii) Routing signals iii) Calling on signals iv) Point indicators v) Modified lower quadrant semaphore signal vi) Miscellaneous signals.

Semaphore signal

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Interlocking:-

It is defined as the technique achieved through mechanical or electrical devices or agencies by which it can be ensured that before a signal is taken to “off” position, for the route ,which the signal controls, is properly set and held, and at the same time all the signals and points , the operation of which may lead to conflicting movements, are locked against the feasibility of such conflicting movements.

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Experiment No:-8

Aim: - Study of points and crossing.

Theory:-

Points, crossings, turnoutsand such related terms are contrivances or

arrangements by which different routes either parallel or diverging are connected

and afford the means for trains to move from one route to another.

Necessity of points and crossings:- The knowledge of the points and crossings is important in following ways for the operating personnel:-

i) Points and crossings provide flexibility of movement by connecting one line to another according to requirements.

ii) They also help for imposing restrictions over turnouts which necessarily retard the movements.

iii) From safety aspect, it is also important as points and crossings are weak kinks or points in the track and vehicles are susceptible to derailments at these places.

Turn outs:-

It is the simplest combination of points and crossings which enables one track either a branch line or a siding, to take off from another track. so the object of

turnout is to provide facilities for safe movement of trains in either direction on both the tracks.

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The above fig contains the following parts of turnout:-

i) A pair of points or switches ii) A pair of stock rails iii) A vee crossing iv) Two check rails v) Four lead rails vi) Switch tie plate vii) Studs or stops.

Left hand and Right hand turnout:-

These are termed as left hand and right hand switches depending upon left or right when seen from the facing direction i.e. stand at the points and look towards the crossing.

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Left hand turnouts

Right hand turn outs

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