Traffic Characteristics Evaluation and Traffic Management Measures: A Case study of Dharwad City

3.1. Spot Speed Study

For the spot speed study, the spot watch method is used. This is one of the simplest methods for spot speed determination. Two reference points are marked on the pavement at a suitable distance apart and an observer starts and stops watch as a vehicle crosses these two marks. From the known distance and the measured time intervals speed are calculated. But this is the least accurate method, therefore in order to check the accuracy of the measure few samples are collected using radar meter. A classified count was conducted between 9.00AM to 12.00PM and 4.PM to 7.00PM on working day.

The spot data is used to calculate the average speed of traffic stream and the safe speed on the stretch. The 50^th percentile speed refers to the average speed and the 85^th percentile speed refers to the safe speed. The frequency distribution table is the convenient method to find the percentile speed.

3.2. Speed and Delay Study

To carry out the speed and delay study, the most convenient method is the Moving car method. In this method, the speed and flow can be obtained by travelling in a car against and with the flow and noting down the journey times, delays, the number of vehicles met with from the opposite direction, a number of vehicles overtaking the test vehicle and number of vehicles overtaken by the test vehicle.

1. To conduct a Travel Time and Delay Study, one must first define the study area by selecting all control points before beginning the study. The time periods recommended for studies are A.M. and P.M. peak hours as well as off-peak hours in the direction of heaviest traffic movements. An average of six round ensures the accuracy in the results [7].
2. These studies should be made during reasonably good weather so that unusual conditions do not influence the study, such as crashes or other unusual delays will produce erroneous results, any runs made during such an occurrence should be terminated and another run conducted. These studies should be conducted during average or typical weekday traffic conditions.

Keeping in view of the above things, the study was conducted in morning peak from 9.00am to 11.00am, evening peak from 5.00pm to 7.00pm and off-peak from 1.00pm to 3.00 pm. The collected will be used to know the running speed and the journey speed of the different corridors. The details of the data and the analysis are given in the next section.

3.3. Traffic Volume Counts for the Design of Road Junctions

For the requirement of road design, it is necessary to know the directional movement of traffic in peak hour. The survey is conducted using stationary enumerators at each arm of the junction to note down the vehicles entering and direction of the exit. Mechanical counters are used to note down the different categories of vehicles. It is sufficient to note down two hours of morning and evening peak [7]. But in order to get the exact peak hour, we took 4 hours in the morning from 8.00am to 12.00pm and evening 4.00pm to 8.00pm to analyze the existing turning movement pattern and to plan the required improvements at the junctions.

The main objective of traffic volume counts is to evaluate the Level Of Service (LOS) at the intersection and at midblock. LOS represents the ease at which the traffic is moving at that particular point. In order to evaluate the LOS, the following data was collected; design hour turning movement volume, vehicle classification for design hour, peak hour factor, prevailing speed, number of lanes on major and minor streets, type of control on minor streets and other geometries of the intersections.

4.1. Spot Speed Study

Three roads were selected to carry out the speed studies, Old PB road, Dandeli road and Saudathi road. These three road pass through the centre of the city and intersect at the Jubilee Circle. Seven locations selected on these three roads are as below along with average spot speeds. L1 and L2 are on Old PB road, L2 and L4 are on Dandeli road, L5, L6 and L7 are on Saudathi road.

L1- Between Jubilee Circle and DHO Circle

L2- Between Jubilee Circle and Court Circle

L3- Dandeli road near KCD

L4- Dandeli road near Jubilee Circle

L5- In front of Corporation office

L6- In front of Azad Park

L7- Between Corporation Circle And CBT circle

The average speed of vehicles on Old PB road towards Belgaum is found to be 31 kmph, towards Bangalore, it is found to be 29 kmph. The speed average speed measured on Dandeli road is 32 kmph, and on Saudathi, road is around 25 kmph. On all the roads, it is observed that speeds of two-wheeler and cars are high, in the range of 30-40kmph. Whereas auto, buses and truck speed is in the range of 25-30 kmph.

The speed of more than 500 vehicles in each direction was found and the tally sheet for the same is given in Tables 3 and 4 represents the frequency distribution table for the three routes are calculated separately to calculate the 15^th, 50^th, 85^th and 90^th percentile speed.

Table 4.

Speed Class (kmph)	Median	Class Frequency (fi)	fivi= i*fi	Percentage of Observation in Class	Cumulative Percentage Observation	-
For Route 1 (Old PB Road)						-
15-19.9	17.5	10	175.0	1.67	1.67	-
20-24.9	22.5	80	1800.0	13.33	15.00
25-29.9	27.5	234	6435.0	39.00	54.00
30-34.9	32.5	188	6110.0	31.33	85.33	-
35-39.9	37.5	56	2100.0	9.33	94.67	-
40-44.9	42.5	19	807.5	3.17	97.83	-
45-49.9	47.5	10	475.0	1.67	99.50	-
50-54.9	52.5	2	105.0	0.33	99.83	-
55-59.9	57.5	1	57.5	0.17	100.00	-
Total		600.000				-
For Route 2 (Dandeli Road)						-
10-14.9	12.5	1	12.5	0.156	0.156	-
15-19.9	17.5	29	507.5	4.531	4.688	-
20-24.9	22.5	68	1530.0	10.625	15.313
25-29.9	27.5	134	3685.0	20.938	36.250
30-34.9	32.5	177	5752.5	27.656	63.906
35-39.9	37.5	133	4987.5	20.781	84.688	-
40-44.9	42.5	56	2380.0	8.750	93.438
45-49.9	47.5	31	1472.5	4.844	98.281	-
50-54.9	52.5	4	210.0	0.625	98.906	-
55-59.9	57.5	3	172.5	0.469	99.375	-
60-64.9	62.5	3	187.5	0.469	99.844	-
65-69.9	67.5	1	67.5	0.156	100.000	-
Total		640.000				-
For Route 3 (Saudathi Road)						-
10-14.9	12.5	10	125.0	2.083	2.083	-
15-19.9	17.5	67	1172.5	13.958	16.042
20-24.9	22.5	170	3825.0	35.417	51.458
25-29.9	27.5	166	4565.0	34.583	86.042	-
30-34.9	32.5	51	1657.5	10.625	96.667	-
35-39.9	37.5	14	525.0	2.917	99.583	-
40-44.9	42.5	1	42.5	0.208	99.792
45-49.9	47.5	2	47.5	0.208	100.000	-
Total		480				-

As it can be observed from Table 4 the exact 15^th, 50^th, 85^th and 95^th percentile speed is not found. Therefore the following method is used to calculate the exact speeds.

Where:

S_D= Speed at P_D, P_D= percentile desired, P_max = higher cumulative percent, P_min = lower cumulative percent, S_max = higher speed and S_min = higher speed

Therefore, the exact 15^th, 50^th, 85^th and 95^th percentile speed for the three routes are as follows,

For Route 1:

For Route 2:

For Route 3:

15^th percentile speed is the lower speed limit at which the vehicle can move, 50^th percentile speed is the average speed of the traffic stream, 85^th percentile speed is the safe speed and 95^th percentile speed is the design speed for the road section.

The average speed for the first route is around 27 kmph and the safe speed found to be 32.44 kmph. For the second route, the average speed is 30kmph and the design speed is 37.67 kmph. The first route is the old PB road which has a relatively higher volume compared to Dandeli road in route 2 as seen from the results.

Similarly, the third route passes through the CBD, and the average speed and the safe speed will much lower than the other two roads i.e. 22.28 kmph and 27.35 kmph, respectively.

4.2. Speed And Delay Study

Journey time studies on a road network in a town are used to evaluate congestion, capacity, level of service and need for improvements. The study was conducted using a moving car technique. Three routes were selected which include all major roads connected to the city i.e. Old PB road, Dandeli road and Saudathi road. The study also covers the CBD area of the city. Route 1 starts from Toll Naka to Shivaji Circle Vis DHO circle, Route 2 starts from KCD circle to Shivaji circle via Kalabhavan circle and Route 3 covers the market area, i.e. from Lakshmi theatre to NTTF via Hanuman temple and Gandhi Chowk. The three routes are shown in Figure 3. The survey data has been analysed to obtain.

• Journey time and journey speed
• Duration, location and cause for delay.
• Running time and running speed.

The results of the study are given in Table 5. The study reveals that the on the major corridor, the delay was at junctions and due to bus stops, and on CBD area, the delay was due to congestion, pedestrian movements and bus stand. The maximum running speed of 31 kmph is observed between Jubilee circle and DHO junction and the minimum of 11 kmph between Gandhi Chowk and CBT circle. On the main road, the average overall journey speed is around 21 kmph, and on CBD area, the speed is around 15 kmph, which means that these two corridors are approaching unstable flow, with tolerable delay i.e. the level of service is D.

The following are the main reasons for greater travel time:

1. On main roads, the delays are due to the intersections.
2. Pedestrians using the carriageway for movement since there are no proper footpaths.
3. Unscientific location of bus stops causing the blockage of narrow carriageways.
4. Presence of crossroads connecting mainstream causing congestion.
5. In the CBD area, the CBT bus stand and old bus stand causes long delays.

4.3. Volume Counts

Classified traffic volume counts are carried out to know traffic characteristics, directional split and hourly variation. A traffic volume count indirectly indicates the capacity utilization. If the traffic is heavy, the road suffers from congestion with consequent loss in journey speeds. Lower speed cause economic loss to the community due to time lost by the occupants of volume counts are, therefore, indicators of the need to improve the transport facilities and is an invaluable tool in the hands of transport planner. A classified count was conducted from 8.00AM to 12.00PM and 4.PM to 8.00PM on working day.

Urban roads are characterized by mixed traffic conditions resulting in complex interaction between various kinds of vehicles. To cater to this, it is usual to express the capacity of urban roads in terms of a common unit. The unit generally employed is the Passenger Car Unit (PCU). PCU values are adopted for different classes of vehicles depending open the percentage of vehicle category as per IRC 106-1990 [8].

Eleven major intersections were selected for the study. The intersections were chosen based on the study area. These intersections lie on the three roads that pass through the city. The peak hour tuning movement for one of the major junction is given in Fig. (4A and B). The consolidated peak hour volume for all the intersections was obtained and is presented in (Table 6).

4.3.2. Junction Improvements

Intersections are to be redesigned to cater to the present day and future traffic and pedestrian volume. Channelising island has to be included to reduce the area of possible conflicts between traffic streams. Establish the desired angle of crossing and merging and serve as pedestrian refuges. The intersections are to be designed considering appropriate turning radius, adequate lanes, appropriate road markings and signboards.

The geometric of all eleven intersections were redesigned by providing necessary elements such as proper median, channelising islands, turning radius, etc, as per IRC SP:41-1994 [9]. Along with this, some of the major roads are proposed for widening from existing two lanes to four lanes. Figs. (5A and B) show the geometries of the junction (DHO) before and after the proposed improvements. As a result, the Shivaji, KCD, CBT and Lakshmi Theater junctions have reached the required LOS. Further, in order to bring all the intersection to the desired LOS, some of the restrictions are proposed.