Traffic speed study

Traffic speed study Report submitted by

Group 4 Nuzhat Nueery Haque

09.02.03.017

Sanchari Halder

09.02.03.022

Md. Aminul Islam

09.02.03.024

Rana Nag

09.02.03.025

Md. Ridwan Bin Alam

09.02.03.026

Md. Mehedi Hassan

09.02.03.027

Submitted to A.K.M. Abir & Md. Sami Hasnaine DEPARTMENT OF CIVIL ENGINEERING

AHSANULLAH UNIVERSITY OF SCIENCE AND TECHNOLOGY

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ABSTRACT

Traffic engineering uses engineering methods and techniques to achieve the safe and time efficient movement of people and goods on roadways. The safe and time efficient movement of the people and goods is dependent on Traffic flow, which is directly connected to the traffic characteristics. The three main parameters of a traffic flow are volume, speed and density. In the absence of effective planning and traffic management of the city, the current road infrastructure cannot cater the future needs of the city. Pedestrian and vehicle volumes have increased significantly in the last decade due to the change of the economics of the middle-class families. Along with which the concern about speed have been rising for a long time. The current work studies traffic speed characteristics in the city of Dhaka at one selected priority junction. In this work emphasis was given on traffic speed data collection and the analysis was carried out through primary traffic flow surveys at Tejgaon-Flyover junction to Shatrasta roundabout in Dhaka city. Traffic flow is studied by manual methods. For better understanding of the present status of traffic flow at the junction, traffic survey is conducted. With the help of the data collection, an attempt had been made to understand the traffic patterns during different time periods. Traffic control at that junction is also dependent on the traffic flow characteristics. Hence the results from the present study are helpful in controlling the traffic at the intersection and also in suggesting some of the remedial measures to improve the traffic safety in the region. Remedial measures such as widening the road, changing 4-lane to 6-lane or by providing more public transport can be recommended based on the outcomes of the work.

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ACKNOWLEDGEMENTS

First of all, we would like to express my deepest sense of gratitude to almighty Allah.

We write this acknowledgement with great honor, pride and pleasure to pay my respects to all who enabled us either directly or indirectly in completing this report.

We express our deep sense of gratitude to A.K.M. Abir, Lecturer, Department of Civil Engineering, and Md. Sami Hasnine, Lecturer, Department of Civil Engineering, Ahsanullah University of Science and Technology for being constant source of inspiration, valuable guidance and constant encouragement to us especially for solving the problems that we have encountered while working on this report.

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DECLARATION We hereby declare that this report is our own work and effort and that it has not been submitted anywhere for any award. All the contents provided here is totally based on our own labor dedicated for the completion of the laboratory experiment of volume study of the road lying near to our university.

Where other sources of information have been used, they have been acknowledged and the sources of informations have been provided in the reference section.

Nuzhat Bueery Haque

Sanchari Halder

Md. Aminul Islam

Rana Nag

Md. Ridwan Bin Alam

Md. Mehedi Hassan

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CONTENTS

Page no Abstract

ii

Acknowledgements

iii

Declaration

iv

Contents

v

List of Figures

viii

List of Tables

ix

Abbreviations

xii

Chapter 1

INTRODUCTION

1

1.1

Objectives

1

1.2

Outline of report

2

1.3

Why do we need a speed study

2

1.4

Scope of Traffic Speed Studies

3

Chapter 2

REVIEW OF LITERATURE

5

2.1 Traffic Survey

5

2.2 Main purposes of traffic survey

5

2.3 Parts of traffic studies

5

2.4 Traffic Speed Study

6

2.5 Definition of speed

6

2.5 a. Spot speed 2.5 a. i.

7 Stopwatch method

7

2.5 a. ii. Radar meter method

13

2.5. a. iii. Pneumatic method

16

2.5. b. Space-Mean-Speed

20 v

Page no 2.5. c. Time-Mean-Speed

20

2.5. d. Free flow speed

21

2.5. e. Travel speed

21

2.5. f. Running speed

22

2.6 Percentile speeds

22

2.7 Reconnaissance Survey

24

2.7 a. Purpose

24

2.7 b. Survey Method

24

2.7 c. Photogrammetry support to highway engineering:

24

2.7 d. Satellite remote sensing:

24

2.7 e. Small format aerial photography (SFAP)

25

2.7 f. Aerial reconnaissance

25

2.7 g. Ground Reconnaissance

25

2.7 h. Instruments for reconnaissance survey

26

Chapter 3

METHODOLOGY

27

Chapter 4

DATA ANALYSIS

30

4.1 Spot speed data of CNG

30

4.2 Service Spot speed data of Bus

31

4.3 Spot speed data of private car

32

4.4 Spot speed data analysis

33

4.5 Travel speed data of private car

36

4.6 Travel speed data of bus

36

4.7 Statistical calculation of travel speed

37

4.8 Comparison of TMS and SMS of two directions

40

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Page no 4.9 Comparison of traffic characteristics of two directions

41

Chapter 5

42

CONCLUSION

5.1 Discussion on spot speed

42

5.2 Discussion on travel speed

42

5.3 Recommendations

42

5.4 Limitations

43

5.5 Recommendations for future work

43

References

44

Appendix-A

Data collection Tables

A.1

Volume data table for individual vehicle

A-1

A.2

Summary Table (Volume Data)

A-2

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LIST OF FIGURES Figure No.

Title

Page No.

2.1

A qualitative time-space diagram

7

2.2

Stopwatch spot speed study

9

2.3

Example stopwatch spot speed study layout

11

2.4

A radar meter

13

2.5

Recording data with radar meter method

14

2.6

Pneumatic road tubes

17

2.7

Road tubes and recorder

17

2.8

Aerial reconnaissance

25

3.1

Map and length of our study zone

27

3.2

A real time snapshot of the road while counting vehicles

29

3.3

Digital stop watch

29

4.1

% Frequency vs spot speed curve

33

4.2

Cumulative % frequency vs spot speed curve

34

4.3

Combination of % Frequency vs spot speed curve and Cumulative % frequency vs spot speed curve

34

4.4

Speed Histogram

35

4.5

Comparison of TMS of two opposite directions

40

4.6

Comparison of SMS of two opposite directions

40

4.7

Operating speed vs V/C plot

41

viii

LIST OF TABLES Figure No.

Title

Page No.

2.1

Stopwatch spot speed study preparation checklist

8

2.2

Recommended spot speed study lengths

8

2.3

Example stopwatch spot speed study distribution table

11

2.4

Radar meter spot speed study preparation checklist

15

2.5

Pneumatic road tube spot speed study preparation checklist 18

2.6

Density range for each level of service

23

4.1

CNG spot speed data

30

4.2

Bus spot speed data

31

4.3

Private car spot speed data

32

4.4

Statistical calculation table of spot speed data of all vehicles33

4.5

Private car travel speed data

36

4.6

Bus travel speed data

36

4.7

Private car travel speed statistical calculation table

37

4.8

Bus travel speed statistical calculation table

38

4.9

Comparison of traffic characteristics of two directions

41

ix

ABBREVIATIONS

SMS

Space Mean Speed

TMS

Time Mean Speed

FPS

Feet Per Second

MPH

Mile Per Hour

ITE

Institute of Transportation Engineers

x

Chapter 1 INTRODUCTION Walking was not fast enough so we ran. Running was not fast enough, so we galloped. Galloping was not fast enough, so we sailed. Sailing was not fast enough, so we rolled merrily along on long metal tracks. Long metal tracks were not fast enough, so we drove. Driving was not fast enough, so we flew. Flying isn't fast enough, not fast enough for us. We want to get there faster. Get where? Wherever we are not. But a human soul can go only as fast as a man can walk, they used to say. In that case, where are all the souls? Left behind. They wander here and there, slowly, dim lights flickering in the marshes at night, looking for us. But they're not nearly fast enough, not for us, we're way ahead of them, they'll never catch up. That's why we can go so fast: our souls don't weigh us down.” ― Margaret Atwood, Bottle People always try to cope up with time. But this is not as easy as it can be said in few words. To cope up with time people need speed and for a good speed people need a transportation system by which s/he can travel to their desired destination in the shortest possible time. But balancing is the intuitive tendency of nature. When a transportation system offers a good speed then a person try to use that system as much as possible and then congestion takes birth. This is the ultimate enemy of speed. If a road system is occupied by a large numbers of vehicles then it is not possible for the travellers to maintain their desired speed which is the consequence of the congestion created by the abnormal number of vehicles occupying the road. Here comes the importance of a transportation engineer. What a transportation engineer does is s/he collects data of a roadway system (Speed data occupies the most important part of them. It mostly indicates the overall efficiency of the traffic system), analyze them and then finally provide the most suitable solution of the problem.

1.1 OBJECTIVES There are several specific objectives of traffic speed studies in this project and is listed below:  To measure the spot speed and travel speed of vehicles and note other related traffic characteristics.  To present detailed diagram of spot speed and travel speed calculations.  To calculate spot speeds and prepare tables for statistical analysis of spot speeds.  To plot histograms, frequency curves and cumulative frequency curves of spot speeds.  To determine weighted average speed, pace, modal speed, speed limit (85th percentile speed), design speed, etc. of spot speeds.  To find Time-Mean-Speed (TMS) and Space-Mean-Speed (SMS) using the travel speed and compare SMS and TMS.

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 To determine various parameters by using these speeds and also to prove some relationships.  To draw Speed(Space-Mean)-flow curve based on observed data.  Superimpose typical speed-flow relationship diagram.  To find LOS of the studied road and to draw detailed diagram.

1.2 OUTLINE OF REPORT The report has been documented in the following manner. The first chapter gives the primary understanding of the problem statement and objectives of the study. The second chapter has been devoted to review of earlier studies to set the guidelines for the present work. The criteria for site selection, method of data collection and theory on traffic speed while the methods we adopted in our data collection system have been discussed in chapter three. Analysis and discussion of results are given in fourth chapter. The specific conclusions drawn from this study and recommendations for further work are given in the fifth chapter.

1.3 Why do we need a speed study Speed is an important transportation consideration because it relates to safety, time, comfort, convenience, and economics. Spot speed studies are used to determine the speed distribution of a traffic stream at a specific location. The data gathered in spot speed studies are used to determine vehicle speed percentiles, which are useful in making many speed-related decisions. Spot speed data have a number of safety applications, including the following: i. Determining existing traffic operations and evaluation of traffic control devices a. Evaluating and determining proper speed limits b. Determining the 50th and 85th speed percentiles c. Evaluating and determining proper advisory speeds d. Establishing the limits of no-passing zones e. Determining the proper placements of traffic control signs and markings f. Setting appropriate traffic signal timing ii. Establishing roadway design elements a. Evaluating and determining proper intersection sight distance b. Evaluating and determining proper passing sight distance (for more information refer to Chapter 3 in the AASHTO Green Book) c. Evaluating and determining proper stopping sight distance

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iii. Assessing roadway safety questions a. Evaluating and verifying speeding problems b. Assessing speed as a contributor to vehicle crashes c. Investigating input from the public or other officials iv. Monitoring traffic speed trends by systematic ongoing speed studies v. Measuring effectiveness of traffic control devices or traffic programs, including signs and markings, traffic operational changes, and speed enforcement programs Other important reasons behind conducting traffic speed study:  To determine traffic speed through high density neighborhoods in order to show any need for speed limit signage, traffic calming measures, or additional law enforcement.  To determine proper speed limits, establish the limits of no-passing zones, determine the proper placements of traffic control signs and markings, and to set appropriate traffic signal timing.  To verify and evaluate speeding problems, assess speed as a contributor to vehicle crashes, or measure the effectiveness of traffic control devices.

1.4 Scope of Traffic Speed Studies: To complete the current experiment of transportation engineering lab-III we have conducted spot speed and travel speed analysis. We have conducted the delay analysis as well. Below is the scopes of spot speed and travel speed studies. Spot speed studies are conducted to estimate the distribution of speeds of vehicles in a stream of traffic at a particular location on a highway and are used for:  Establishing the effectiveness of new or existing speed limits and/or enforcement practices  Establishing trends to assess the effectiveness of national policy on speed limits and enforcement  Specific design applications (like sight distance, breaking distance, passing distance etc.)  Specific control applications (yellow/all red timing – the size of dilemma zone depends on speed)  Investigation of high-accident locations at which speed is suspected to be a causative factor

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Travel speed study determines the amount of time required to travel from one point to another on a given route. Often, information may also be collected on the locations, durations, and causes of delays. Travel speed is used for:      

Efficiency check Collection of rating data Model calibration Collect data for economic analysis (user costs) Evaluation of performance before and after improvement Problem location identification

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Chapter Two REVIEW OF LITERATURE

To design a roadway there are specific road elements that must be determined. Some of these are the number of lanes, lane width, median type and width, length of acceleration and deceleration lanes for on and off ramps, need for truck climbing lanes for roadways with steep grades, curve radii required for vehicle turning, and the roadway alignment required to provide adequate stopping and passing sight distance (Mannering and Kilareski 1998). The geometric features of the road such as horizontal and vertical alignment sight distance and in many cases, cross-section, are sensitive to the design speed.

2.1 Traffic Survey Traffic engineers and planners need information about traffic. They need information to design and manage road and traffic system. They use the information for planning and designing traffic facilities, selecting geometric standards, economic analysis and determination of priorities. They use this to justify warrant of traffic control devices such as signs, traffic signals, pavement markings, school and pedestrian crossings. The also use this information to study the effectiveness of introduced schemes, diagnosing given situations and finding appropriate solutions, forecasting the effects of projected strategies, calibrating and validating traffic models. Transportation system is a dynamic system. Information about traffic must be regularly updated to keep pace with ever-changing transportation system. Data must be collected and analyzed systematically to get representative information. Traffic surveys are the means of obtaining information about traffic. This is a systematic way of collecting data to be used for various traffic engineering purposes.

2.2 Main purposes of traffic survey: The main purposes of traffic survey are: traffic monitoring, traffic control and management, traffic enforcement, traffic forecasting, model calibration and validating etc.

2.3 Parts of traffic studies: Traffic studies include:       

Inventory of road traffic physical features Traffic stream characteristics- volume, speed, density, occupancy studies etc. Capacity studies of streets and intersections System usage studies- Travel time and delay, O-D survey Travel demand- home interview survey Road users cost- Value of travel time, vehicle operating cost Parking supply & demand studies

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   

Axle load survey Mass transit performance and usage studies Traffic accidents studies Environmental impact studies of transport

2.4 Traffic Speed Study Traffic speed data are needed in research, planning, designing and regulation phases of traffic engineering and are also used in establishing priorities and schedules of traffic improvements. The traffic engineer must acquire general knowledge of traffic speeds in order to set different limits, setting different distances i.e. passing sight distance, stopping sight distance etc.

2.5 Definition of Speed: In simple words, speed is defined as the distance travelled in a unit time. Speed is expressed in m/s, fps, mph etc. units. Speed is given by:

v

v

x t

dx dt

(2.1)

(2.2)

Where, x = Distance (mile or meter or feet) t = Time (second or hour) Speed acquired by using Eq 2.1 will give the average speed. If Eq 2.2 is used the instantaneous speed will be found. Graphically speed can be measured from time space diagram. Time space diagram is a diagram in which position of a vehicle is plotted against time chronologically. A qualitative time-space diagram is shown in Fig 2.1.

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Fig 2.1: A qualitative time-space diagram Types of speed:      

Spot speed Space-Mean speed Time-Mean speed Free flow speed Travel speed Running Speed

2.5 a. Spot speed Spot speed is the instantaneous speed of a vehicle as it passes a specified point along a road. Spot speeds may be determined by manually measuring (with use of electronic or electromechanical devices like pneumatic tube detectors or radars) the time required for a vehicle to traverse a relatively short specified distance. Methods for spot speed data collection: There are several methods for collecting spot speed data. Some of them are: i. Stopwatch method ii. Radar meter method iii. Pneumatic method 2.5 a. i. Stopwatch Method The stopwatch method can be used to successfully complete a spot speed study using a small sample size taken over a relatively short period of time. The stopwatch method is a quick and inexpensive method for collecting speed data.

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Preparation Checklist for a Stopwatch Spot Speed Study When preparing for a spot speed study using a stopwatch, use the checklist in Table 2.1. The checklist may be modified or expanded as necessary. Table 2.1: Stopwatch Spot Speed Study Preparation Checklist Ö When Complete Notes Step Obtain stopwatch Obtain backup stopwatch Obtain 50–100 foot tape Obtain data collection forms Obtain hardhat and safety vest Obtain brightly colored reference posts Select time and day Contact local law enforcement Other:

Key Steps to a Stopwatch Spot Speed Study A stopwatch spot speed study includes five key steps: 1. Obtain appropriate study length. 2. Select proper location and layout. 3. Record observations on stopwatch spot speed study data form. 4. Calculate vehicle speeds. 5. Generate frequency distribution table and determine speed percentiles. Obtain Appropriate Study Length The study length is important because it is used in the calculation of vehicle speeds. Table 2.2 provides recommended study lengths, which are based on the average speed of the traffic stream. Using these recommended study lengths makes speed calculations straightforward and less confusing. If these lengths are not appropriate, another length can be used assuming it is long enough for reliable observer reaction times. Table 2.2: Recommended Spot Speed Study Lengths Traffic Stream Average Speed Recommended Study Length(feet) Below 25 mph 88 25–40 mph 176 Above 40 mph 264

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Select Proper Location and Layout Figure 2.2 illustrates a typical layout for conducting a spot speed study using a stopwatch. When selecting a location and layout, care must be exercised so that the observer can clearly see any vertical reference posts. The observer should be positioned higher than the study area and be looking down. The position could be on a bridge or a roadway back slope. The observer should use reference points to aid in collecting the elapsed time it takes a vehicle to travel through the study area. The reference point to start timing may be a brightly colored vertical post. The reference point to end timing may be a tree or a signpost in the observer’s sight line. An accurate sketch of the site should be documented, including number of lanes, position of observer, and description of reference points (see Figure 2.2 for an example).

Fig 2.2: Stopwatch spot speed study Record Observations on Stopwatch Spot Speed Data Form On the stopwatch spot speed data form (a blank form is provided in Appendix A.1), the observer records the date, location, posted speed limit, weather conditions, start time, end time, and down time. As the front wheels of a vehicle (or only the lead vehicle in a group) cross a mark or pavement crack at the beginning of the predetermined study length, the observer starts the stopwatch. The watch is stopped when the vehicle’s front wheels pass a reference line in front of the observer. A slash is recorded on the data form corresponding to the elapsed time observed. Calculate Vehicle Speeds To calculate vehicle speed, use the predetermined study length and the elapsed time it took the vehicle to move through the course (as recorded on the stopwatch data form) in the following formula: v

D 1.47T

(2.3)

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where V = spot speed (mph), D = length (feet), and T = elapsed time (seconds). In the equation, 1.47 is a constant that converts units of feet per second into miles per hour. For example, if the spot speed study length is 150 feet and the motorist’s elapsed time is 4.23 150 feet seconds, the motorist is travelling at  24.12mph . 1.47 * 4.23 Example Stopwatch Spot Speed Study The city of Cottonwood Glen received a complaint of afternoon traffic speeding in a residential area. The city suspected this was related to students leaving a nearby high school. The first action taken by the city was to quantify the facts by conducting a spot speed study. The city decided to use the stopwatch method because of their limited resources. A location was selected near the intersection of 4th Street and University Avenue, approximately two blocks from the high school and where the city had received multiple speeding complaints from residents. The posted speed limit is 30 mph. The study was conducted on a Wednesday and started at 3:00 p.m. The time was selected to correspond to the period when most high school students leave the school. The study continued until a sample size of 100 vehicles was measured. The study length of 176 feet was used because the posted speed limit is between 25 and 40 mph, as shown in Table 2.2. The study layout is illustrated in Figure 2.2.

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Fig 2.3: Example Stopwatch Spot Speed Study Layout The vertical reference point is the “begin timing” reference. A tree is the “stop timing” reference point. This vertical reference point helps with the accuracy of timing by providing a line-of-sight to aid the observer Table 2.3: Example Stopwatch Spot Speed Study Distribution Table

The study shows that the 50th percentile or median speed falls between 27.2 and 28.9 mph, and the 85th percentile of speed falls between 33.3 and 35.2 mph. Equation 2.1 is used to

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find the exact speeds for the 50th and 85th percentiles of speed. For the 50th percentile of speed, PD = 50% Pmax = 54% Pmin = 41% S max = 28.9 mph S min = 27.3 mph SD 

50%  41% (28.9mph  27.2mph)  27.2mph = 28.4 mph 54%  41%

For the 85th percentile of speed, PD = 85% Pmax = 92% Pmin = 83% S max = 35.2 mph S min = 33.3 mph 85%  83% (35.2mph  33.3mph)  33.3mph = 33.7 mph 92%  83% If the 85th percentile of speed would have been 5 mph or more above the posted speed limit, then following actions could have been considered: SD 

   

Adjust the posted speed limit. Increase speeding enforcement. Initiate traffic calming measures. Conduct public awareness efforts.

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2.5. a. ii Radar meter method

Fig 2.4: A radar meter A radar meter is a commonly used device for directly measuring speeds in spot speed studies (see Figure 2.4). This device may be hand-held, mounted in a vehicle, or mounted on a tripod. The effective measuring distance for radar meters ranges from 200 feet up to 2 miles (Parma 2001). A radar meter requires line-of-sight to accurately measure speed and is easily operated by one person. If traffic is heavy or the sampling strategy is complex, two radar units may be needed.

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Fig 2.5: Recording data with radar meter method. Different sized vehicles and the detection of the observation vehicle may affect radar readings (Currin 2001). Large vehicles such as trucks and buses send the strongest return signal to the radar meters and as a result smaller vehicles may not be detected. If there is a presence of large vehicles, the observer may need to record the speeds of vehicles that are alone. Also, some vehicles are equipped with radar detectors to warn them that a radar unit is operating in their vicinity. Drivers will slow down when warned by a detector. It is not unusual for other drivers to slow down also. This slowing will affect the study results. The radar unit may be turned off while not in use so radar detectors cannot detect it. Radar Meter Spot Speed Study Preparation Checklist When preparing for a spot speed study using a radar meter, use the checklist in Table 2.4. The checklist may be modified or expanded as necessary.

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Table 2.4: Radar Meter Spot Speed Study Preparation Checklist Step

Ö When Complete

Obtain radar meter Read instructions and safety directions for the radar meter Obtain backup battery Obtain tripod to support radar meter Create data collection forms Obtain hardhat and safety vest Select time and day Contact local law enforcement Other: Because of its cost, a radar meter may be the most difficult piece of equipment for an agency to obtain. A radar meter can be purchased, or one may be obtained (rented or borrowed) from a local law enforcement agency. Key Steps to a Radar Meter Spot Speed Study A radar meter spot speed study includes four key steps: 1. Select proper location and placement of radar meter. 2. Determine an appropriate selection strategy. 3. Record observations on radar meter spot speed study data form. 4. Generate frequency distribution table and determine speed percentiles. Select Proper Location and Placement of Radar Meter Proper placement of the radar meter at the study area is critical. The positioning of the radar unit is determined by the capabilities of the radar unit (as listed in the users’ manual). The unit should also be concealed from the view of motorists. Effective ranges may be up to 2 miles, but as the distance increases the effectiveness decreases (Robertson 1994). The least accurate position, which often results in no readings at all, is obtained when the meter is aimed at a 90-degree angle to the roadway centerline (Homburger et al. 1996). An accurate sketch of the site should be documented, including number of lanes, position of observer, and description of reference points. Determine an Appropriate Selection Strategy Except for studies conducted under low-volume conditions, it is impossible to obtain a radar measurement for every vehicle. For peak flow analysis, speeds are measured during the peak

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period. For assessing general speed trends or for setting speed limits, off-peak measurements are more appropriate. The selection of the target vehicle that represents the vehicle population under study is also important. A good question to ask is, “What type or types of vehicles are of concern—cars, trucks, buses, or others?” Typically cars, station wagons, pickup and panel trucks, and motorcycles are classified as passenger cars. Other trucks and buses are classified as trucks. School buses and farm equipment may be recorded separately. When the target vehicle is defined, a selection strategy is developed to provide a random sample. A random sample will reduce the tendency to select the vehicles that stand out. For example, the observer could obtain a speed reading from every fourth vehicle or every tenth vehicle. Record Observations on Radar Meter Spot Speed Data Form On the radar meter spot speed data form (a blank form is provided in Appendix), the observer records the date, location, posted speed limit, weather conditions, start time, end time, and down time. A slash is recorded on the data form corresponding to speed observed for each selected vehicle (or only the lead vehicle in a group) under the appropriate vehicletype classification. Generate Frequency Distribution Table and Determine Speed Percentiles Determine the 50th and 85th speed percentiles using a frequency distribution table and calculations as described earlier. 2.5 a. iii. Pneumatic road tube method The pneumatic road tube method is normally used for longer data collection time periods than those of either the stopwatch or radar meter method. Using this method, pneumatic tubes are placed in the travel lanes (see Figure 2.6) and are connected to recorders located at the side of the road (see Figure 2.7).

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Fig 2.6: Pneumatic Road Tubes

Fig 2.7: Road Tubes and Recorder

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The automatic recorders are capable of storing large amounts of individual vehicle data or even larger amounts of vehicle classification data. The collected data are downloaded from the recorder to a laptop computer or portable floppy disk drive in the field, or via telephone modem to a centrally located computer. Pneumatic Road Tube Spot Speed Study Preparation Checklist: When preparing for a spot speed study using pneumatic road tubes, use the checklist in Table 2.5. The checklist may be modified or expanded as necessary. Table 2.5: Pneumatic Road Tube Spot Speed Study Preparation Checklist Ö When Complete Step Obtain equipment Read users’ manual Obtain measuring tape for spacing tubes Obtain software Obtain scissors for trimming tubes Select method for attaching tubes to the roadways Obtain recorders Obtain new batteries for recorders Obtain hardhat and safety vest Select time and day Select location Involve corresponding jurisdiction to provide traffic control Other: Pneumatic road tube spot speed studies require specialized equipment and knowledge of how to maintain the equipment. Few jurisdictions have the equipment to adequately complete this study; most jurisdictions require assistance from the Iowa DOT or a consulting firm. Information on contracting for a spot speed study. Key Steps to a Pneumatic Road Tube Spot Speed Study A pneumatic road tube spot speed study includes four key steps (Robertson 1994): 1. Perform necessary office preparations. 2. Deploy and calibrate data collection equipment. 3. Check data and retrieve equipment. 4. Generate frequency distribution table and determine speed percentiles.

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Perform Necessary Office Preparations During office preparations, coordinate all data collection activities with appropriate state and local officials, including transportation, traffic, and law enforcement agencies. For example, you may coordinate with state or local officials in obtaining traffic control for the deployment and recovery of equipment. The field team must be briefed on the data collection process to ensure that all observers are collecting the same type of data. The team should assemble and inspect all tools, supplies, and equipment. Each piece of equipment should be tested in advance of using. Deploy and Calibrate Data Collection Equipment The road tubes are prepared on the roadside to minimize the time each traffic lane is closed. Workers then place the road tubes across the lanes. The location of the tubes should be outside the influence of other factors such as an intersection, major access points, etc. The separation of the pneumatic tubes should be 2–15 feet. For the specific spacing of the pneumatic tubes refer to the users’ manual. Traffic control should be provided to protect the crew. After placing, the crew should make sure that the tubes are functioning properly. Finally, the crew can secure the road tubes to the pavement. To avoid theft, the recorder should be secured. Check Data and Retrieve Equipment The accuracy of the equipment in measuring the speeds of the traffic stream should be checked. The recorder first measures the elapsed time it takes the vehicle to pass over the tubes. Then this time interval is converted to the corresponding spot speed. The elapsed time can be checked with a stopwatch. The crew can adjust the recorder until the correct speeds are being recorded. It is advisable to check the function and accuracy of the equipment at least once during every 24-hour data collection period. When the data collection period has ended, the recorded data should be checked again for accuracy. Crews recover data collection equipment by reversing the process they used to deploy it. Generate Frequency Distribution Table and Determine Speed Percentiles Determine the 50th and 85th speed percentiles using a frequency distribution table and calculations as described earlier.

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2.5 b. Space-Mean-Speed (SMS) Space-Mean-Speed is the average of vehicle speeds weighted according to how long they remain on the section of road. Mathematically it is harmonic mean of the observed speeds. It is given by:

us 

1 1 N

i N

1  i 1 U i

(2.4.a)

Or,

us 

nd i n

(2.4.b)

t

i

i 1

Where, ti = observed time for the i th vehicle to travel distance d N or n = number of vehicles observed d= length of roadway section

2.5 c. Time-Mean-Speed (TMS) The time mean speed Ut, is the arithmetic mean of spot speeds of all vehicles passing a point during a specified interval of time. It is given by,

1 Ut  N

n

U

i

i 1

(2.5.a)

or, i n

u ut 

i

i 1

n

(2.5.b)

where, Ui or ui = observed speed of i-th vehicle N or n = number of vehicles observed

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Space-mean speed and time-mean speed are not equal. For general usage, no distinction is normally made between both speeds, for theoretical and research purposes WARDROP has shown in his calculations that

 s2 ut  us  us

(2.6)

where  s2 = variance of the space distribution of speeds

2.5 d. Free flow speed: The desired speed of drivers in low volume conditions and in the absence of traffic control devices. In other words, the mean speed of passenger cars that can be maintained in low to moderate flow rates on a uniform freeway segment prevailing roadway and traffic conditions. Factors affecting free flow speed:       

Width Lateral clearance Number of lanes Side friction Interchange density Geometric design Weather (The amount of reduction in free-flow speed is directly related to the severity of the weather event).

 Visibility.

2.5 e. Travel speed Travel speed is the effective speed of the vehicle on a journey between two points and is the distance between the two points divided by the total time taken for the vehicle to complete the travel including any stopped time. If the journey speed is less than running speed, it indicates that the journey follows a stop-go condition with enforced acceleration and deceleration. The spot speed here may vary from zero to some maximum in excess of the running speed. Uniformity between travel and running speeds denotes comfortable travel conditions.

21

2.5 f. Running speed Running speed is the average speed maintained over a particular course while the vehicle is moving and is found by dividing the length of the course by the time duration the vehicle was in motion. i.e. this speed doesn't consider the time during which the vehicle is brought to a stop, or has to wait till it has a clear road ahead. The running speed will always be more than or equal to the travel speed, as delays are not considered in calculating the running speed.

2.6 Percentile speeds 98th Percentile Speed/Design speed: The speed at or below which 98 percent of a sample of free flowing vehicles is traveling (based on a spot speed study). 85th Percentile Speed/Safe speed: The speed at or below which 85 percent of a sample of free flowing vehicles is traveling; this is typically used as a baseline for establishing the speed (based on a spot speed study. 50th Percentile Speed/Median speed: The speed that equally divides the distribution of spot speeds, 50 percent of observed speeds are higher than the median, 50 percent of observed speeds are lower than the median. In practice, the exact 50% and 85% (50th and 85th percentiles) are not found in the cumulative percent column. To reach these exact percentages, a calculation is completed using percentages and speeds from the distribution table. Shown below is the equation for calculating speed percentiles:

SD 

PD  Pmin ( S max  S min )  S min Pmax  Pmin

(2.7)

where S D = speed at PD , PD = percentile desired, Pmax = higher cumulative percent, Pmin = lower cumulative percent, S max = higher speed, and S min = lower speed. Design speed Design speed is defined as the maximum safe speed that can be maintained over a specified section of highway when conditions are so favorable that the design features of the highway govern (ITE 1999). This definition implies that the design speed should be selected based on drivers expectations, the type of highway and terrain and topography.

22

When applying the design speed as the main criteria in setting the speed limit, the posted speed is usually lower than the design speed because it is known that some drivers will speed and also the road conditions may sometimes be worse than the ones that were used in design standards (Persaud et. Al 1997). However from a driver’s point of view a speed limit set using this base will appear unrealistic as the speed affects the design of a relatively few elements but is used to classify an entire highway segment. For example, long tangent sections in flat terrain have a higher design speed than sections with curvilinear alignment and this is perceived as such by the driver. Thus, when 5 km of roadway is used to set the speed limit for 50 km of highway it is unreasonable to the driver and leads to substantial speed limit violations. In addition the actual conditions may be worse than the conditions assumed for the design. This would lead to factors such as acceleration and deceleration rates and the coefficient of friction between the tire and road being lower than what was assumed in the standards. Thus a permanent speed limit based in design speed may not necessarily be safe all of the time. The 1997 Highway Capacity Manual notes that speed is a major indicator of service quality to drivers. Freedom to maneuver within the traffic stream and proximity to other vehicles are equally important to a driver. Further the density increases as the flow increases up to capacity to a broad range of flows. Thus, density is the primary performance measure used to provide an estimate of the level of service. The following table shows the density ranges for each level of service: Table 2.6: Density range for each level of service: Level of Service A B C D E F

Density Range (pc/mi/in) 0-10.0 10.1-16.0 16.1-24.0 24.1-32.0 32.1-45.0 >45.0

23

2.7 Reconnaissance survey 2.7 a. Purpose The main objective of reconnaissance survey is of examining the general character of the area for the purpose of determining the most feasible routes, or routes, for further more detailed investigations. Data collected should be adequate to examine the feasibility of all the different routes in question, as also to furnish the Engineer-in-charge with approximate estimates of quantities of costs, so as to enable him to decide on the most suitable alternative or alternatives. The survey should also help in determining any deviations necessary in the basic geometric standards to be adopted for the highway facility. 2.7 b. Survey Method The reconnaissance survey may be conducted in the following sequence (a) Study of topographical survey sheets, agricultural, soil, geological and meteorological maps, and aerial photographs, if available. (b) Aerial reconnaissance (where necessary and feasible) (c) Ground reconnaissance (including another round of aerial reconnaissance for inaccessible and difficult stretches, where called for). 2.7 c. Photogrammetric support to highway engineering: Photogrammetric technology is also useful to the highway engineer in many ways. Large scale maps on scales of 1:2,000 to 1:25,000 can be very precisely produced through photogrammetric process. The contouring can also be produce, the common intervals depending on the height of the camera. Very minute and precise measurements amounting to sub-mere accuracy can be obtained. In other words, profile (with height values) and crosssections across highway center-line can be extracted from optical model. 2.7 d. Satellite remote sensing: This technique is used with the help of satellites. At present, it gives resolution of the order of 6 meters. Photographic products of imagery are available from National Remote Sensing Agency, Hyderabad on scales of 1:12,500, 1:25,000 and 1:50,000. Digital products are also available in floppy cartridges and tapes. The cartridge/tape can be digitally processed in the computer and the image on the monitor can be interpreted with the possibility of enhancement of quality through manipulation of image processing software. Major advantages of satellite imagery is its repeatability as orbiting satellites visit the same spot on earth every few weeks. Thus, the latest information regarding the physical features (like, the extent of a town or urban area, etc.) can be obtained to update on available map. The information on natural resources namely, geology, geomorphology, land use, soil status (waterlogging, erosion, etc.), drainage, forest extent, etc. as available may be most useful input for the planners of highway alignment.

24

2.7 e. Small format aerial photography (SFAP): In case of large projects with mapping as one of the main objectives conventional aerial photography in traditional format (23 cm x 23 cm) may also be useful. There are at least there known agencies in India for such aerial photography, namely he National Remote Sensing Agency (NRSA), Hyderabad, Air Survey Company, Calcutta and the India Air Force. All aerial photography work requires clearance from the Ministry of Defence. The major advantages of SFAP are:- Very large scale true colour photography can be done in scales upto 1:1,000 to 1:2,000 (upto scales of 1:10,000). Acquisition plan alongside highways can be suitably made in scale of 1:4,000. Monitoring of urban areas, villages and environment along the corridor are possible at comparatively lower cost than ground surveys. 2.7 f. Aerial Reconnaissance An aerial reconnaissance will provide a bird’s eye view of eh alignments under consideration along with the surrounding area. It will help to identify factors which call for rejection or modification of any of the alignment. Final decision about the alignments to be studied in detail on the ground could be taken on the basis of the aerial reconnaissance.

Fig2.8: Aerial Reconnaissance 2.7 g. Ground Reconnaissance The various alternative routes located as a result of the map study are further examined in the field by ground reconnaissance. As such, this part of the survey is an important link in the chain of activities leading to selection of the final route.

25

General reconnaissance consists of general examination of the ground walking or riding along the probable route and collecting all available information necessary for evaluating the same. In the case of hill sections, it may sometime be advantageous to start the reconnaissance from the obligatory point situated close to the top. If an area is inaccessible for the purposes of ground reconnaissance, recourse may have to aerial reconnaissance to clear the doubts. While carrying out ground reconnaissance, it is advisable to leave reference pegs to facilitate further survey operations. 2.7 h. Instruments for reconnaissance survey Instruments generally used during ground reconnaissance include compass, Abney level/Altimeter, Pedometer, Aneroid barometer, Clinometer, Ghat trace, etc. Walkie-talkie sets, mobile phone and pagers are useful for communication, particularly in difficult terrain. Use of the instruments mentioned above to obtain ground slopes, maximum gradients, elevation of critical summits or stream crossing, and location of obligatory points, serve as a check on the maps being used. In difficult hilly and forest terrain assistance of new technology, like Global Position System (GPS) or Differential GPS (DGPS) may also be taken where the magnitude and importance of the work justify their provision. GPS is a comparatively new technology which utilizes the satellites orbiting around the earth. A minimum of four satellites are needed to indicate the coordinates (X, Y, Z) on the ground at any time of day and night with accuracy of a few centimeters, two geo-receivers are sued and this mode of using two GPS is known as differential GPS (DGPS).

26

Chapter Three Methodology Flyover

Shatrasta

Fig 3.1 Map and length of our study zone The acquisition of the data, its evaluation and analysis will be discussed below. These are discussed in order to show the relevant steps in the analysis of the data. Acquiring the speed data A background of the equipment used to collect the speed data is presented below to familiarize the reader with these aspects of the provincial transportation agency. Location: Location of the spot for traffic speed survey was chosen to be from Tejgaon flyover to Shatrasta. Vehicles from Tejgaon flyover to Shatrasta and from Shatrasta to Tejgaon flyover were counted. We stood by the side of the road and data of different vehicles were collected by different persons. Date: Data for speed study was collected on 20 June 2013. It was Thursday and it was a weekday. Time: Time of data collection for volume study was different for different groups however for group-4 the time was from 9:00 am to 9:15 am Weather Condition: It was initially a sunny day but afterwards it became cloudy.

27

Observation: Classified Vehicle Counts. Duration: 30 minutes for spot speed study and 30 minutes for travel speed study. Equipments used to collect speed data The data analyzed for this report was collected from practical observation on the road from AUST-flyover to Shatrasta roundabout. The data collectors used stopwatches to record the time in case of recording spot speed data. In the other hand travel speed data was collected by number plate method. Half of the enumerators stood on one end whereas the other half stood on the other end. Then they recorded the number plates of the vehicles passing through that end. 2 video camares were also used for recording the number plates in case of cross checking. After collecting data those data were recorded on a excel spreadsheet and various graphs were plotted using Microsoft-Excel spreadsheet. Number of Enumerators: Six. Methodology of reconnaissance survey Before going for the actual work we have conducted a reconnaissance survey on the previous day of actual work. Due to lack of instruments we could not adopt any of the methods described in chapter 2. We just visited the spot of study and divided the whole road length into five equal sections. And then we have selected the reference points where we collected speed data. And on the day of operation we went directly to the spot and collected speed data. But if we could conduct the actual reconnaissance work then we would have good understanding of the whole formation of the study zone.

28

Fig 3.2: A real time snapshot of the road while we were accumulating traffic speed data

Fig3.3: Digital stop watch

29

Chapter Four Data Analysis

4.1 Spot Speed data of CNG Table 4.1: CNG spot speed data Veh No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Speed(mph) 24.35785 30.37991 30.15734 29.40341 27.62736 56.779 26.81744 27.81404 30.83504 22.49441 28.19505 25.88979 32.2861 38.47175 33.1974 23.86364 29.61494 22.86932 36.91908 34.02047

Veh No. 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37

Speed(mph) 31.78747 17.3691 27.62736 24.94835 29.09171 31.30401 28.29194 31.06775 35.33457 16.97516 23.93301 24.94835 28.78655 20.89582 28.78655 25.97147 20.3786

30

4.2 Spot Speed data of Bus Table 4.2: Bus spot speed data Veh No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Speed(mph) 19.37166 25.72798 10.97727 25.72798 32.93182 31.66521 27.81404 20.73792 17.29612 24.50284 36.429 26.47252 28.3895 34.16164 29.29877 41.79165 34.44751 28.00325 30.95096 28.3895 32.93182 31.18543

Veh No. 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

Speed(mph) 41.79165 29.29877 27.72039 41.58058 34.7382 38.47175 34.16164 36.91908 36.91908 34.16164 38.29281 21.3843 27.62736 27.62736 22.80597 19.28092 36.26852 26.81744 31.42349 27.90832 25.33217

31

4.3 Spot Speed data of Private car Table 4.3: Private Car spot speed data

Veh No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Speed(mph) 37.42252 38.11553 33.6039 33.74162 39.58151 29.5088 34.02047 39.58151 39.58151 33.46729 32.67045 43.56061 39.39213 52.4392 31.91068 43.79231 37.76585 41.37163 33.1974 45.99416 38.65237 44.98882 39.77273 46.77815 43.79231

Veh No. 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Speed(mph) 36.75426 44.50246 39.58151 43.33134 37.5934 28.00325 33.3318 32.41321 44.98882 42.00487 44.98882 36.429 51.45597 36.75426 34.44751 36.429 31.66521 47.31583 33.46729 33.6039 36.59091 42.87997 28.78655 34.8854

32

4.4 Spot speed data analysis Table 4.4: Statistical calculation table of spot speed data of all three vehicles

Class

Mid Value Frequency % frequency Cumulative % frequency 0-5 2.5 0 0 0 5-10 7.5 0 0 0 10-15 0.775194 0.775194 12.5 1 15-20 3.875969 4.651163 17.5 5 20-25 10.07752 14.72868 22.5 13 25-30 24.03101 38.75969 27.5 31 30-35 26.35659 65.11628 32.5 34 35-40 19.37984 84.49612 37.5 25 40-45 10.85271 95.34884 42.5 14 45-50 2.325581 97.67442 47.5 3 50-55 1.550388 99.22481 52.5 2 55-60 0.775194 57.5 1 100 60-65 61.5 0 0 100 Total Frequency = 129

30 25

% frequency

20 15

Pace = 26.5 - 36.5 mph

10

Modal Speed = 31.5mph

5 0 0 -5

10

20

30

40

50

60

70

Spot speed, mph

Fig 4.1: % Frequency vs Spot speed curve

33

100

Design Speed

% cumulative frequency

90

85th percentile speed

80 70 60 50

50th percentile speed

40

15th percentile speed

30 20

29.5

49

37.5

22.5

10 0 0

10

20

30 40 Spot speed, mph

50

60

70

Fig 4.2: % Cumulative frequency vs Spot speed curve If we combine the above two graphs then we will get the percentage of vehicles below which the vehicles are in modal speed we will get the range percentage of vehicles that are in pace. In the following figure a combination is presented. 100 90 80

% frequency

70

32.5% to 81% vehicles are in pace

60 50

59% vehicles are in modal speed

40

Pace = 26.5 - 36.5 mph

30

Modal Speed = 31.5mph

20 10 0 0

10

20

30 40 Spot speed, mph

50

60

70

Fig 4.3: Combination of % Frequency vs Spot speed curve and Cumulative frequency vs Spot speed curve

34

Speed Histogram 40 34

35

31

% frequency

30 25 25 20 14

13

15 10 5 5 0

3

1

2

1

0

0 Speed Range 0 to 5

5 to 10

10 to 15

15 to 20

20 to 25

25 to 30

35 to 40

40 to 45

45 to 50

50 to 55

55 to 60

60 to 65

30 to 35

Fig 4.4: Speed Histogram

35

4.5 Travel speed data of Private Car Table 4.5: Private car travel speed data

Vehicle No. 1 2 3 4 5 6 7 8 9 10 11 12

Speed (mph) 16.23376623 21.30681818 19.36983471 27.49266862 23.03439803 19.82029598 21.30681818 18.73126873 21.30681818 18.93939394 17.39332096 24.35064935

4.6 Travel speed data of Bus Table 4.6: Bus travel speed data Vehicle No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Speed (mph) Vehicle No. 11.91989828 15 18.73126873 16 17.04545455 17 22.72727273 18 14.82213439 19 22.42822967 20 23.34993773 21 16.0806175 22 19.36983471 23 18.32844575 24 28.40909091 25 18.13346228 26 14.95215311 27 18.52766798 28

Speed (mph) 20.53669222 16.87668767 30.43831169 16.71122995 13.97168405 13.42161775 13.52813853 19.15219612 21.30681818 19.36983471 30.43831169 19.36983471 21.30681818 18.93939394

36

4.7 Statistical calculation of travel speed Table 4.7: Private car travel speed statistical calculation table

Vehicle No. 1 2 3 4 5 6 7 8 9 10 11 12

Speed (mph)

TMS or SMS or Arithmatic Harmonic Mean ( ) Mean ( ) (mph) (mph)

16.23376623 21.30681818 19.36983471 27.49266862 23.03439803 19.82029598 21.30681818 18.73126873 21.30681818 18.93939394 17.39332096 24.35064935

∑ ∑ =

.

=

=20.77

=20.37

(

Standard deviation (

.

−

)

(

−

)

20.61225 0.284068 1.971224 45.14269 5.110134 0.909242 0.284068 4.172088 0.284068 3.365184 11.42789 12.79358 106.36

.

)=

= 3.11 Now,

+

= 20.37 +

. .

= 20.84 ≈ 20.77

So wardrop relation is satisfied with a % error of

.

. .

∗ 100 = 0.34%

37

Table 4.8: Bus travel speed statistical calculation table

Vehicle No.

Speed (mph)

1

11.91989828

2

18.73126873

3

17.04545455

4

22.72727273

5

14.82213439

6

22.42822967

7

23.34993773

8

16.0806175

9

19.36983471

10

18.32844575

11

28.40909091

12

18.13346228

13

14.95215311

14

18.52766798

15

20.53669222

16

16.87668767

17

30.43831169

18

16.71122995

19

13.97168405

20

13.42161775

21

13.52813853

TMS or SMS or Arithmatic Harmonic Mean ( ) Mean ( ) (mph) (mph)

(

−

)

54.36262892 0.315542018 5.05146057 11.79422917 19.98863933 9.829665053 16.45874377 10.31940135 0.005903573 0.930364905

∑ ∑

83.10311346 =

.

=19.293

=

.

1.344527719

=18.3

18.84295172 0.585733094 1.546770347 5.838565282 124.2179726 6.665536609 28.3164034 34.4731295 33.23362779

Contd…. 38

22

19.15219612

23

21.30681818

24

19.36983471

25

30.43831169

26

19.36983471

27

21.30681818

28

18.93939394

0.019825733 4.055463669 0.005903573 124.2179726 0.005903573 4.055463669 0.125037246 (

Standard deviation (

)=

−

)

599.71

.

= 4.7 Now,

+

= 18.3 +

. .

= 19.5 ≈ 19.29

So wardrop relation is satisfied with a % error of

.

. .

∗ 100 = 1.1%

39

4.8 Comparison of TMS and SMS of two directions: 50 45 40

15 10 5 0

Flyover Shatrasta

20

Shatrasta-flyover

25

Flyover Shatrasta

TMS of group-4 and group-10

30

Shatrasta-flyover

35

Bus

Private Car Group-4

Group 10

x

Fig 4.5: Comparison of TMS of two opposite directions 45 40

30

10 5

Shatrasta-flyover

15

Flyover Shatrasta

20

Shatrasta-flyover

25

Flyover Shatrasta

SMS of Group 4 and 10

35

0 Bus

Private Car Group 4

Group 10

Fig 4.6: Comparison of SMS of two opposite directions

40

45 40 Operating speed

35 30 25 20 15 10 5 0 0

100

200

300

400

500

v/c

Fig 4.7: Operating speed vs v/c plot

4.9 Comparison of traffic characteristics of two directions

Different forms of speeds Spot speed (TMS) Travel speed (TMS) Spot speed (SMS) Travel speed (SMS) Safe speed (85th percentile) Design speed (98th percentile) Median speed Modal speed Pace Speed limits

Flyover to Shatrasta 32.76 mph 19.74 mph 30.7 mph 18.9 mph 37.5 mph 49 mph 29.5 mph 31.5 mph 26.5 mph - 36.5 mph 29.5 mph - 49 mph

Flyover to Shatrasta 26.96 mph 40.76 mph 26.49 mph 39.66 mph 29.3 mph 31.7 mph 26.1 mph 23.15 mph 22 mph - 32 mph 26.1 mph - 29.3 mph

41

Chapter Five Discussion and Recommendation The following conclusions are drawn from present study. 5.1. Discussion on spot speed: There were a large variety of speeds in the roadway we studied. It was understood when we took data from the field. At first we assumed that the representative vehicles will fulfill our desire of study but afterwards we felt the shortcomings of our assumptions. The percentage frequency curve and the cumulative percentage frequency curve was smooth enough. And from the charts we could calculate the modal speed, pace and different percentile speeds flexibly. Different charts are shown in chapter 4. 5.2. Discussion on travel speed: We collected data of a large number of vehicles from either side but we were successful to collect only a few number of buses and private cars speed data. Data of some groups were not available due to which we could not construct various other graphs. In fig-4.7 in chapter 4 there is operating speed vs v/c plot. Which we plotted with only data of 4 groups (Gr-1, Gr-4, Gr-7, Gr-10). If we see the graph then it will be clear that it is not a good graph. However we tried to fulfill all the requirements to complete the report. 5.3 Recommendations 1. Optimum vehicle composition of a traffic flow consists of 40% public transport or BUS while there was only 27% public transport in our study road. 2. The buses we observed on the road were too much old that they could not maneuver easily although the maneuverability of buses is originally low. So replacing these old buses with new ones is highly recommended. 3. Bicycle should have specific lanes of their own which typically is placed beside the footpath/shoulder. But there was not any specific lane in the road we studied. So it is recommended that a lane system should be introduced to increase efficiency of the road at the same time there should be a bicycle specific lane. 4. NMT or electrical low speed vehicles should not be permitted in this type of arterial road. Although they typically travel on the left lane but they create a drag force which slows down the high speed vehicles which creates congestion. 5. There were some large container trucks observed on the road. Congestion can be slightly avoided if these vehicles were allowed only at off peak hours.

42

5.4 Limitations 1. The major limitation of this volume study was the survey was conducted for 15 minutes only, whereas for proper results the survey should be conducted for at least 3 hours 2. Number of enumerators was 5 to 6 persons per group where for complete and precise collection of data at least 15 to 20 persons were required for each group. 3. We collected data for representative portion of traffic stream. However if it was possible to collect data for each and every type of vehicle then a better scenario could have been presented. 5.5 Recommendations for future work The present study is focused mainly on traffic speed only. Various other experiments could be conducted depending on the data we had in out possession. However due to lack of time we conduct those extensive experiments and it is suggested that those studies should be conducted in future to have a good understanding of the traffic condition of the roadway we studied in this time.

43

References Robertson, H. D. 1994. Spot Speed Studies. In Manual of Transportation Engineering Studies, ed. H. D. Robertson, J. E. Hummer, D. C. Nelson. Englewood Cliffs, N.J.: Prentice Hall, Inc., pp. 33–51. Currin, T. R. 2001. Spot Speed Study. In Introduction to Traffic Engineering: A Manual for Data Collection and Analysis, ed. B. Stenquist. Stamford, Conn.: Wadsworth Group, pp. 4–12. Homburger, W. S., J. W. Hall, R. C. Loutzenheiser, and W. R. Reilly. 1996. Spot Speed Studies. In Fundamentals of Traffic Engineering. Berkeley: Institute of Transportation Studies, University of California, Berkeley, pp. 6.1–6.9. Parma, K. 2001. Survey of Speed Zoning Practices: An Informational Report. Washington, D.C.: Institute of Transportation Engineers. Persaud, Bhagwant, Parker, Martin Jr., and Gerald Wilde. 1997. Safety, speed and speed management. Transportation Canada Repor. Ottawa Canada. Pline, James L. editor. 1999. Traffic Engineering Handbook. Institute of Transportation Engineers (ITE), 5th Edition. Mannering, Fred L. Walter P. Kilarski. 1998. Principles of Highway Engineering and Traffic Analysis. Wiley, New York. 2nd Edition:340. National Research Council. 1998. Highway Capacity Manual; Special Report 209. 3rd Edition Washington, D.C.

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