TITLE : INTERSECTION VOLUME STUDY
OBJECTIVE : To determine the rate of traffic flow in an intersection area for 4-leg junctionsor T-junctions.
THEORY : Before the planning and designing the traffic system can be done is necessary to collect traffic data to analyzed, and studied in depth. Field surveys are needed to make a detailed plan. The data collected will be sufficient for the data to represent an actual situation on the characteristics of traffic in the area. Information is often collected in the field is counting traffic volume,traffic speed, travel time alternator and traffic accident statistics.
APPARATUS : Counter, stop watch, paper data, safety vest and stationery. LOCATION : Jalan Raja Musa Mahadi
PROCEDURE :
1) A suitable site along Jalan Raja Musa Mahadi was selected near the entrance of the polytechnic. (the site choosen make sure that it is not dangerous and does not interfere with existing traffic.
2) The traffic flow at the selected area were determined. The number of vehicles and the type of each vehicle for every five minutes based on the Jalan Raja Musa Mahadi are recorded. Every five minutes, the vehicles a were being classes.
3) The observation was done for 1 hour
4) The total of PCU for every five minutes intervals for all types of vehicles were assumed as shown in the table below.
RESULT
Vehicles count into PCU :Analysis according to 5 minutes interval in PCU :
DIRECTION 5 10 15 20 25 30 35 40 45 50 55 60 TOTAL ROAD A 7 17 23 13 25 24 21 20 27 13 30 15 235 ROAD B 13 10 5 10 11 13 0 14 8 17 8 5 114 ROAD C 35 31 53 23 21 29 35 46 33 33 27 26 392 ROAD D 6 12 8 3 7 6 10 9 8 6 5 3 83 ROAD
DIRECTION ROAD A ROAD B ROAD C ROAD D
TOTAL %
Vehicle Type P.C.U % P.C.U % P.C.U % P.C.U % P.C.U %
Passenger car 183.00 81.3 68.00 62.2 323.00 81.5 52.00 62.0 626.00 76.9 Motorcycles 17.49 7.8 16.83 15.4 37.62 9.5 10.89 13.0 82.83 10.2 Light Van 8.75 3.9 10.50 9.6 10.50 2.7 10.50 12.5 40.25 4.9 Med. Lorries 15.75 7.00 14.00 12.8 22.75 5.7 10.50 12.5 63.00 7.7 Heavy Lorries 0.00 0.0 0.00 0.00 2.25 0.6 0.00 0.0 2.25 0.3 Buses 0.00 0.0 0.00 0.00 0.00 0.0 0.00 0.0 0.00 0.0 TOTAL ∑=224.99 100 ∑=109.33 100 ∑=396.12 100 ∑=83.89 100 ∑=814.33 100
Analysis for traffic movement in junction for Road A, B and C :
DIRECTION TRAFFIC MOVEMENT TOTAL
RIGHT TURN TROUGH LEFT TURN VOLUME P.C.U
ROAD A 82 161 - 243 ROAD B 67 47 - 114 ROAD C 72 334 - 406 ROAD D 12 72 - 84 % 27.5 72.5 - 100 TOTAL 233 614 - 847
RAJA MUSA MAHADI ROAD
ROAB B
ROAD A ROAD C
No of vehicles vs time 0 100 200 300 400 500 600 700
Passenger Car Motorcycle Van Lorry Heavy Lorry Bus
Number of Vehicles versus Type of Vehicles
0 10 20 30 40 50 60 70 80 90 100 5 10 15 20 25 30 35 40 45 50 55 60 Number Of vehicles Time,second
Sample of calculation
Passenger car : 183 X 1.00 = 183.00 p.c.u % = X 100 = 81.30 % ~8.45-8.50 (ROAD A) =7 X 1.00 =7.00 ~8.50-8.55 (ROAD A) =(12X1.00)+(4X0.33)+(1X1.75)+(1X1.75)
=12+1.32+1.75+1.75 -> TAKE WHOLE NUMBER =12+1+2+2
=17
i) Optimum cycle time,Co Assume w=3.25 S(pcu/h) =1860 Phase 1: N-S YN = qN / SN = =0.06 Ys = qs/Ss = =0.05
Select maximum value , Y1 = 0.06 Phase 2 : E-W YE = qE / SE = =0.22 Yw = qw / Sw = = 0.13
Select maximum value, Y2 = 0.22
Therefore,
Y = Y1 +Y2
= 0.06+0.22
=0.28
Optimum cycle time, Co = L = [ 1 + ( I1 – a1) + [𝞴2 + (I2-a2)] L= [10+ (7-3.5) +[9+(7-3.5)] L= 13.5+12.5 L=26 s Co = ( ) = 61.1
ii) Determination of signal settings a) Phasing -> two phase
b) Cycle time c) Amber time
Table below ... d) All red
e) Green time for each phasing
Colour ROAD A ROAD B ROAD C ROAD D
Green-amber 0 20 00 s 0 40 30 s 0 24 66 s 0 40 16 s Amber-red 0 02 99 s 0 04 05 s 0 03 01 s 0 03 79 s Red- green 1 59 05 s 143 40 s 1 56 83 s 1 36 79 s
iii) Comments the existing signalized intersection.
The signal system is not that much effective. Because there is a lot of lost time. In this are the car is not that much. So the time should be change for the cycle time. Road B and D is not important compare to Road A and Road C. Road C is the main road the more vehicles travel. So the signalized intersection must change to automatic traffic system. Which means it automatic so the ally change the colour of traffic signal when there is no car.
iv) Propose improvement on the existing traffic signal.
The traffic signal must change to automatic traffic signal. So, it more easier than nowadays traffic signal. If the system not that much effective than on a peek hours there can be a traffic police for guide the traffic flow. It must be done so the congestion of traffic flow can reduce.
Discussion
1. Study method using count method
Two methods are available for conducting traffic volume counts: (1) manual and (2) automatic. Manual counts are typically used to gather data for determination of vehicle classification, turning movements, direction of travel, pedestrian movements, or vehicle occupancy. Automatic counts are typically used to gather data for determination of vehicle hourly patterns, daily or seasonal variations and growth trends, or annual traffic estimates.
MANUAL COUNT METHOD
Most applications of manual counts require small samples of data at any given location. Manual counts are sometimes used when the effort and expense of automated equipment are not justified. Manual counts are necessary when automatic equipment is not available.
Manual counts are typically used for periods of less than a day. Normal intervals for a manual count are 5, 10, or 15 minutes. Traffic counts during a Monday morning rush hour and a Friday evening rush hour may show exceptionally high volumes and are not normally used in analysis; therefore, counts are usually conducted on a Tuesday, Wednesday, or Thursday.
2. Manual Count Recording Methods
Manual counts are recorded using one of three methods: tally sheets, mechanical counting boards, or electronic counting boards.
Tally Sheets
Recording data onto tally sheets is the simplest means of conducting manual counts. The data can be recorded with a tick mark on a pre-prepared field form. A watch or stopwatch is necessary to measure the desired count interval.
3. The existing signalised intersection is not suitable for the traffic flow because during the peak hours the traffic will be congested. Therefore, a good solution should be made to avoid this problem become worst in the future. This may cause the maintenance to be done
frequently to maintain the road in a good manner for the road users.
4. The cycle time is also not suitable for the traffic flow because it more than 2 minutes. As the JKR standard, the cycle time must be less than 2 minutes. Therefore, the signal settings must be updated based on the study made time to time.
Conclusion
As the conclusion, the intersection volume study is very important for the design of the traffic flow for the road along the Raja Musa Mahadi. The study needs many data to design the junction efficiently. The junction must be designed according to the JKR standard (BS standard) to ensure the road users have a safe journey.
