speed spot studies

CC 503 TRAFFIC ENGINEERING

APPRECIATION

Thanks God, we give thanks 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 extent 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.

SPEED SPOT STUDIES 1


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.



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 capacity 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 have 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 away

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.



THEORY

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


V V VEHICLE

Student A 3Students Student B

Positions of Students and flags


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 study 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



APPARATUS

The following apparatus is required. No. APPARATUS FIGURE DESCRIPTION

1. Stop Watch

-To make that experiment-To support the load

2. Measuring Wheel-To record the value

of the load.

3. Two Flags-To hang the load

4. Safety Vest-To support and hold the load.



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.



5. Transfer and calculate for the relevant data into the Frequency Form.

6.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)

7.Dtermine the following speed characteristics:a) Mean speedb) Median sppedc) Mode class (speed)d) 85-th Percentile speede) 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.



RESULTS & CALCULATION

Calculation

a) Class interval = R

1+3.322 logn

= 84.31−37.821+3.322 logn

= 8.74 ≈ 9

b) Arithmetic mean speed , x=∑fvn

= 1205.18

20

= 60.259

c) Median = L+

( n2−fl )×C

[ fm ]

= 54.81+

( 202−30 )×9

35 = 49.67

d) Standard deviation, s = √¿¿ = √¿¿ = 11.30



Graph

41.80 50.31 59.31 68.31 77.31 86.310

1

2

3

4

5

6

7

8

Frequency Histogram for Spot Speed Studies

speed, (km/hr)

freq

uenc

y of

car

30.00 40.00 50.00 60.00 70.00 80.00 90.000

5

10

15

20

25

30

35

40

Frequency Distribution Curve

speed (km/hr)

perc

enta

ge o

f tot

al o

bser

vatio

n



30.00 40.00 50.00 60.00 70.00 80.00 90.000

20

40

60

80

100

120

Percentage Of Cumulative Frequency



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.



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.



CONCLUSION

Field traffic studies strengthened the traffic theories presented in the class room. Spot

speed study and intersection analysis and signal assessment 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 laboratory will include additional studies

and projects that will embrace the transportation material taught in the classroom environment..



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/



APPENDIX


speed spot studies

Documents