Dr. S. Moses Santhakumar
Post Graduate Student
Department of Civil Engineering, Regional Engineering College Tiruchirappalli – 620 015.
It has been the experience of many traffic planners that most transportation plans rarely progress beyond the drawing board due to lack of financial resources and other related constraints. The only recourse open to the traffic manager therefore is the option of optimising existing facilities to provide improved accessibility and mobility at a satisfactory level of safety and comfort to most of the road users. This can be achieved by studying and evaluating the problem in the light of sound and tested traffic management techniques, which are essentially low cost, easily implement and flexible. These are short-term solutions, primarily intended to reduce the intensity of inconvenience caused by congestion. They may not offer a permanent solution, yet they lend themselves to some time earning relief up to a point where the administration may launch the long term and short term planning. Objective of short-term solutions should be within the perspective and is compatible with the goals set out in the long-term measures. Though the identification of the problems and the correct diagnosis may automatically suggest the usefulness of a particular management technique, the application of the single technique, in isolation, is rarely sufficient in bringing about a significant improvement in the Level Of Service (LOS) and transportation mobility of an area. More often than not, the problems shifted to the adjacent locality or an entirely new problem is spawned as a consequence of the very technique used as a solution, if applied in isolation. It is therefore, essential to seek solutions in a combination of techniques, even in a relatively local situation, for effective management (Venkateswaralu, 1996). A solution must be observed as a part of the total scenario and the systems approach used to prepare a Transportation System Management (TSM) Plan for the entire network.
The traffic management techniques that have been tried all over the world have been listed below in seven main categories:
|Regulatory Techniques||Bus Priority Techniques|
|Traffic Control Devices||Self – Enforcing Techniques and|
|Traffic Segregation Techniques||Police – Public Interaction Techniques|
|Demand Management Techniques|
2. Geographic Information System (GIS)
GIS is a computer-based tool for mapping and analysing things that exist and events that happen on earth. GIS technology integrates common database operations such as query and statistical analysis with the unique visualization and geographic analysis benefits offered by maps. These abilities distinguish GIS from other information systems and make it valuable to a wide range of public and private enterprises for explaining events, predicting outcomes, and planning strategies (Moses Santhakumar, 1998). GIS stores information about the world as a collection of thematic layers that can be linked together by geography. This simple but extremely powerful and versatile concept has proven invaluable for solving many real-world problems from tracking delivery vehicles, to recording details of planning applications, to modeling global atmospheric circulation.
GIS allows us to bring all types of data together based on the geographic and locational component of the data. But unlike a static paper map, GIS can display many layers of information that is useful to us (www.esri.com). We will be able to integrate, visualize, manage, solve, and present the information in a new way. Relationships between the data will become more apparent and the data will become more valuable. GIS gives us the power to create maps, integrate information, visualize scenarios, solve complicated problems, present powerful ideas, and develop effective solutions like never before.
3. The Study Area
The Madurai Local Planning Area (LPA) has been taken for the study. Madurai is the second largest City in Tamilnadu State, having a very old history of about two thousand six hundred years and is often referred to as the Athens of East. It has three National Highways namely NH-7, NH-45B, NH-49 and state highways passing through it. The study area is limited to Madurai Local Planning Area (LPA). The land use details of the urban and rural settlement of the Local Planning Area are given in Table 1.
Table 1. Land use Details of Madurai LPA.
|Sl.No||Land use zone||Area (ha)||Percentage of developed area|
|5||Public and semi-public||181.79||7.48|
Source: CTTS Report for Madurai Local Planning Area, 1997
The heavy settlement has made Madurai as highly congested. The area for transportation infrastructure is less than ten percent of the developed area leading to transportation problems in the LPA. Different transportation system management measures that can be applied feasibly during the present and the future conditions of Madurai LPA road network are discussed below. For that purpose forecasting of future traffic and capacity calculation for different road links are made.
4. GIS Based TSM
4.1.Forecasting the Traffic
The traffic volume for the year 2002 and future year 2007 are forecasted with respect to the 1997 traffic volume taken from the CTTS Report (CTTS Report, 1997), vehicle growth rate and the sample survey conducted at different locations. However, the capacity restraints are not taken into account. The traffic volume count made at different selected locations the percentage share of each type of vehicle is computed. As per IRC: 106-1990 (IRC: 106, 1990) the PCU values are assigned and the total PCU share of each vehicle is obtained on each link. Fig. 1 shows the traffic flow in the CBD.
Based on the registered vehicle data collected from the Regional Transport Office Madurai North and South the growth rate of each type of vehicle is calculated. For the unregistered vehicles like bicycle and cycles rickshaws the growth rate was obtained through the general enquiry made at different cycle marts and cycle rickshaw unions that is mentioned in the growth rate table. For forecasting traffic on NH, SH, MDR’s overall growth rate of 12 percent is taken.
Fig. 1 Peak Hour Traffic Flow in CBD
4.2. Road Capacity Calculation
Capacity of all the links are made with three different categories:
- Capacity with parking
- Capacity with restricted parking
- Capacity without parking
The capacity of road links as per HCM 1985 is 1300-1500 PCU per lane per hour. Adopting the average value of 1400 and a lane width of 3.50 m, the capacity is computed as 400 PCU/hr per one metre effective width of carriage way.
The following formula is adopted for the calculation of capacity,
Capacity = Effective width of road way * 400 PCU/hr
To obtain the effective width of road, road inventory survey was conducted and total width (after encroachment) and parking width are measured. For the different cases the effective width is taken as,
Effective width with parking = Total width – parking width
Effective width without parking = Total width
Effective width with restricted parking = Total width – parking width allowed.
The width of parking allowed is computed by adopting the following four conditions:
|Total road width (m)||Parking width allowed (m)|
|Less than 5 m||0.0|
|>5 m and 10 m and|