CC 503
TRAFFIC ENGINEERING
APPRECIATION
Thanks God, we give thanks tha nks to the Almighty for His grace and we can set up a report entitled ‘Traffic Engineering (CC 503)'. Appreciation and gratitude goes to Mr. Syed as lecturer traffic engineering for their help, cooperation, guidance, advice and practical ideas that poured along the run. Thankfully we have colleagues who help others and help each other work, here are our group members Roffandi, Luqman, Nurul Shafiqa, Asyikin, Effah and Amiera are always striving to complete this traffic engineering work. Moreover, not least thank you to friends, colleagues and all those who have helped us either directly or indirectly. Hopefully reports this produced a certain ex tent helped to increase the effectiveness student learning and enhance students' knowledge in the subjects studied civil engineering in general and in particular traffic engineering.
Thank you.
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INTRODUCTION
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. For a spot speed study at a selected location, a sample size of at least 50 and preferably 100 vehicles is usually obtained (Ewing 1999). Traffic counts during a Monday morning or a Friday peak period may show exceptionally high volumes and are not normally used in the analysis; therefore, counts are usually conducted on a Tuesday, Wednesday, and Thursday. Spot speed data are gathered using one of three methods: (1) stopwatch method, (2) radar meter method, or (3) pneumatic road tube method. These methods are described in this chapter in order from least expensive to most expensive. The stopwatch method is the least expensive and least accurate of the methods.
To Analyse the Speed and the amount of vehicles on a determined road. Spot Speed is the average speed of vehicles passing a point, or the time mean speed. 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. Carried out by recording the speeds of a sample of vehicles at a specified location. 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.
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OBJECTIVE
SPOT SPEED STUDY To determine the speed characteristics of traffic at the location. Spot speed studies are vital for measuring different variables and factors needed in the design and analysis of the highway system. Observed speeds are used for c apacity analysis, geometric design, safety measures, speed trends and assessment. Speed studies aid in the decision making processes and in before-and-after studies to assess the effectiveness of roadway modifications. Also, speed observations help determine whether the roadway is in need of new law enforcement, realignment, or reconstruction. Spot speed data ha ve a number of safety applications, including the following: determining existing traffic operations and evaluation of traffic control devices, establishing roadway design elements, and measuring effectiveness of traffic control devices or traffic programs, including signs and markings, traffic operational changes, and speed enforcement programs. Because of the importance of such speed studies, data has to be collected properly and presented effectively. Therefore required to select a section of a road outside the university campus and awa y from close intersections and unusual traffic activities. Information about the selected section of the road is gathered such as section speed, number of lanes, and general description of location. Data is to be collected during off peak periods on a week day.
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THEORY
V
V
Student A
3Students
VEHICLE
Student B
Positions of Students and flags
Figure 1 : Positions of Students and flags
Spot speed data are gathered using methods :
Stopwacth method Radar meter method Pneumatic road tube method. Measuring wheel Two Flags Safety Vest
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These methods are described in this chapter in order from least expensive to most expensive.The stopwatch method is the least expensive and least accurate of the methods. The stopwatch method can be used to successfully complete a spot speed stud y using a small sample size taken over a relatively short period of time. The stopwatch method in a quick and inexpensive method for collecting speed data.
Figure 2 : Stopwatch Spot Speed Study Layout
Merlimau town noticed a large number of traffic jams in the morning along Main Street. The city decided to conduct a speed study to see how the speed of the vehicle compared to the recorded the speed limit. The police department offered their radar meter to be used and so the city decided to meter using radar to conduct spot speed. The city has determined that it will not need help from members of local law enforcement
Figure 3 : Example Radar Meter Spot Speed Study Layout
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APPARATUS The following apparatus is required.
No.
1.
2.
APPARATUS
FIGURE
DESCRIPTION
Stop Watch
-To make that experiment -To support the load
Measuring Wheel
-To record the value of the load.
-To hang the load 3.
4.
Two Flags
-To support and hold the load.
Safety Vest
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PROCEDURE (After done setup apparatus, follow the procedures below)
Test Procedure : No.
Procedure
Picture
1.
Identify the spot at which the speed data will be collected.
2.
Use the measuring wheel to get a 100m distance..
3.
Record the times taken for 20 passenger cars in the Form.
4.
Based on the Form , determine the mean, maximum and minimum speed of vehicles according to their class. Comment on your findings.
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5.
6.
7.
TRAFFIC ENGINEERING
Transfer and calculate for the relevant data into the Frequency Form.
Plot the following : a) Frequency Histogram ( Percentage of vihicles vs. Speed) b) Frequency Distribution Curve (Percentage of vihicles vs. Speed) c) Cumulative Frequency Distribution Curve (Cumulative frequency vs. Speed)
Dtermine the following speed characteristics: a) Mean speed b) Median spped c) Mode class (speed) d) 85-th Percentile speed e) Standard deviation
8.
Comment your findings.
9.
Does your findings justify the problems of speeding at the location? If it does what are your recommendations.
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RESULTS & CALCULATION Calculation
= = 8.74 ≈ 9 Arithmetic mean speed , = =
a) Class interval =
b)
c)
⁄ Median = ⁄) ( = = 49.67
d) Standard deviation, s =
√ √ =
= 11.30
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Graph
Frequency Histogram for Spot Speed Studies 8 7
R 6 A C F 5 O Y C 4 N E U Q3 E R F 2 1 0 41.80
50.31
59.31
68.31
77.31
86.31
SPEED, (KM/HR)
Frequency Distribution Curve 40
N35 O I T A V30 R E S B O25 L A T O20 T F O E 15 G A T N10 E C R E P 5 0 0.00
20.00
40.00
60.00
80.00
100.00
SPEED (KM/HR)
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Percentage Of Cumulative Frequency 120
100
80
60
40
20
0 0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
SPEED SPOT STUDIES
80.00
90.00
100.00
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DISCUSSION 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 coloured 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.
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RECOMMENTDATION
Other reason happened outcome of experiment inaccuracy was: Essential to this initial step is to identify the reason for conducting the study and nature of the problem to be evaluated. Other considerations for the study plan are the date and time during which the study should be completed, and the number of vehicles that should be observed as part of the study. The timing of the study should be consistent with the reason for conducting the study. For example, if the study is being completed to determine if speed complaints are valid during the evening rush hour, then the study should be completed during the evening rush hour. Literature suggests that speed data be collected for a minimum of one hour and observe at least 30 vehicles, however depending upon the type of technology used to complete the study, and the complexity of the study, sample sizes and durations can often include thousands of vehicles over multiple 1 days. Once the plan is completed, the study can be carried out and the data can be evaluated as outlined in the steps below.
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CONCLUSION
Field traffic studies strengthened the traffic theories presented in the class room. Spot speed study and intersection analysis and signal as sessment helped students gain the following benefits: Spot speed study and intersection analysis and signal assessment field study implementations, familiarity with standard procedures and standard forms, data presentation techniques, data analysis, field experience and applications, group work, professional presentation skills, interpretations of results, and professional software implementation. Students presented their suggested solutions to improve the studies intersections such as signal timing modifications, intersection widening, geometric adjustments, and realignments. This paper described the minimum requirements for establishing the aforementioned studies and intended objectives. Future plans are to develop an additional three-hour laboratory to accompany the transportation engineering class. The labo ratory will include additional studies and projects that will embrace the transportation material taught in the classroom environment..
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REFERENCES
Book References
Transportation Engineering (KAS 4172) lecture notes. Currin, Thomas R., Introduction to traffic engineering, a manual for data collection and analysis, Brooks/Cole, Pacific Grove, CA, 2001.
Internet References
http://www.roadtraffic-technology.com
http://www.popcenter.org/learning/speeding.html
http://www.ctre.iastate.edu/pubs/traffichandbook/
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APPENDIX
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