Future Impact on Maharagama Town Traffic Flow and Pedestrian Safety due to Southern Expressway and Outer Circular Highway: Proposed Solutions

: Maharagama town becomes severely congested due to traffic & pedestrian activities during daytime. The absence of proper road shoulders makes the pedestrians enter the carriageway, which in turn creates a safety hazard and results in slowing down vehicular traffic. After the completion of the Southern Expressway and Outer Circular Highway, it is expected that additional traffic volume in Maharagama town area will result in traffic congestion and safety situation even worse. In order to find a solution for this situation, capacities of roads were evaluated by compiling data of vehicular flow, pedestrian movements and other supportive information of that area for present condition and for year 2030 (i.e. 20 years from now) with do nothing option. According to the obtained field data, and capacity calculations, all the roads in this area will badly fail to cater to the future traffic demand (i.e. for year 2030) unless some drastic improvements are conducted immediately. Also it was found that even at present, available pedestrian facilities were not satisfactory in this area, and the rate of accidents were high. Hence road widths, number of lanes, walkway shoulders, and pedestrian crossings were designed using the US highway capacity manual to evaluate the above conditions in the zone. Also geometric designs for islands were conducted based on AUSTROADS guides and templates. Objective of this study is to introduce suitable layout plan for Maharagama town area with required road improvements, road signs, and pedestrian facilities to enhance traffic flow and pedestrian safety for future operational conditions with the Southern Expressway and Outer Circular Highway in operation.


Introduction
Maharagama town is administered by the Maharagama Urban Council and it's situated around A4 (High Level Road), about 15 km away from the centre of the commercial capital Colombo. Town area governed by the Maharagama Urban Council and is around 1.245 km 2 .
As Figure 1 indicates, the study area was selected between Maharagama Bo-tree junction (A) to President's College junction (C) along Old Road (distance of about 800m) and along High Level Road (distance of 820m). Administrative authority of these two main roads is the Road Development Authority. In the selected study area there are four main three legged intersections. They are Bo-tree junction (A), Pamunuwa junction (B), President's College junction (C) and Clock tower junction (D) as indicated in Figure 1.

Introduction
Maharagama town is administered by the Maharagama Urban Council and it's situated around A4 (High Level Road), about 15 km away from the centre of the commercial capital Colombo. Town area governed by the Maharagama Urban Council and is around 1.245 km 2 .
As Figure 1 indicates, the study area was selected between Maharagama Bo-tree junction (A) to President's College junction (C) along Old Road (distance of about 800m) and along High Level Road (distance of 820m). Administrative authority of these two main roads is the Road Development Authority. In the selected study area there are four main three legged intersections. They are Bo-tree junction (A), Pamunuwa junction (B), President's College junction (C) and Clock tower junction (D) as indicated in Figure 1.

Introduction
Maharagama town is administered by the Maharagama Urban Council and it's situated around A4 (High Level Road), about 15 km away from the centre of the commercial capital Colombo. Town area governed by the Maharagama Urban Council and is around 1.245 km 2 .
As Figure 1 indicates, the study area was selected between Maharagama Bo-tree junction (A) to President's College junction (C) along Old Road (distance of about 800m) and along High Level Road (distance of 820m). Administrative authority of these two main roads is the Road Development Authority. In the selected study area there are four main three legged intersections. They are Bo-tree junction (A), Pamunuwa junction (B), President's College junction (C) and Clock tower junction (D) as indicated in Figure 1.
The Colombo-Matara Highway (also known as the Southern Expressway) is partially constructed at present. This will link the Sri Lankan capital Colombo with Matara, a major city in the south of the country. This 128 km expressway once fully completed will be 26 m wide, (ie. Including 3 lanes each direction, centre-median, and 2 emergency lanes on either side). Initially it will have 4 lanes up to Galle from Makumbura with the remainder having 2 lanes. The entire expressway will later be widened to six lanes [1].
Outer Circular Highway (OCH) is an access control road encircling Colombo. The 29 km (18 mile) long Outer Circular Road will connect with proposed Colombo-Matara Expressway and with proposed Colombo-Katunayake Expressway (under construction) and will provide an orbital beltway to bypass the city of Colombo. On completion, this highway will provide access to existing national highways (i.e. A and B class roads) and proposed expressways at several interchanges, and as such will serve as the basis for the entire network of highways and expressways in the country [1]. The main objective of the Outer Circular Highway is to disperse traffic congestion and encourage development away from the highly populated urban areas in the western province achieving a better balance for physical and economic growth.
It is observed that during peak hours Maharagama town area gets severely congested due to traffic & pedestrian activities. As a solution currently a one-way road system is introduced around Maharagama, but still the problem is not addressed completely. Therefore people waste time on the road which they could use more productively when passing Maharagama town.

Aim and Objectives
The Maharagama town area is already congested by traffic and pedestrian activities. One of the major problems for congestion at Maharagama town is because of excessive pedestrian movements taking place due to number of wayside textile traders occupying Maharagama town area as their business grounds. Also this business community disturbs the walkways and pedestrians have to use the carriageways for their movements. The obvious solution for this situation is, to transfer this business activity away from the congested locations. Also unavailability of a central bus stand is causing a major transportation issue in Maharagama. This has resulted in large amount of cross transfers across the roads. In future, according to the normal growth, the traffic volume will rapidly increase. In addition, after the implementation of the Southern Expressway and Outer Circular Highway it can be expected to create a high volume of additional traffic to the roads within the study area.
The aim of this study is to identify whether the existing road capacities are enough to cater to the current traffic volume and also for the future traffic. Then to Explore possibility to improve the roads by introducing suitable road widths and number of lanes at study area to cope with the traffic needs at a reasonable level of service, while enhancing the safety of pedestrians.
In achieving the above aim, there are some interim objectives that have to be satisfied. Following concerns have been addressed in this study.

3.2
Traffic and pedestrian studies Following traffic data gathering exercises were conducted.
Measure the volume of daily traffic flow according to vehicle types on relevant roads in Maharagama.
Identification of peak flows.
Conduct turning movement surveys.
Conduct highway capacity analysis.
Carry out pedestrian volume surveys.
Conduct pedestrian travel pattern studies.

3.3
Accident study Collect accident records from Maharagama Police Station.
Identify the high risk accident locations. (i.e. Black spots).
Ranking them using suitable method.
Recommend proper treatments to those accident prone locations.

3.4
Capacity checks Highway capacity checks were conducted for High Level Road, Old Road, Dehiwala Road, and Pamunuwa Road for the present and future traffic flows to check on their satisfactory performance. These roads were evaluated to see whether they could carry the flows satisfactorily. During the study if found that road widths and lanes do not satisfactorily cater to the future traffic, they were redesigned using the highway capacity manual.
Pedestrian data was obtained by conducting pedestrian surveys and analyzed these data to check the pedestrian safety with increasing population and traffic growth for year 2030. Crosswalks and sidewalks were redesigned after checking for population growth, since it was found that present facilities and conditions were not of acceptable standards. Traffic and pedestrian islands were designed to provide pedestrian safety and to minimize accidents in this study area.
Also field surveys were done to evaluate the dimensions of roads and pedestrian crossings within the study area at present. Furthermore turning movement surveys were carried out.

4.
Data and Analysis 4.1 Identification of peak hour From the 24 hour MCC traffic data, morning, mid-day and evening peak hours within the study area were identified. There were two major peak hour ranges; morning peak from 7.30 to 8.30 am and the evening peak from 17.30 to 18.30 pm. Since, Maharagama town area experienced heavy traffic (both vehicular and pedestrian) during mid-day, the field studies were also focused during the day time too.

4.2
Distance between intersections and pedestrian crossings. Distances between intersections and crossings were measured and are indicated in Figure 3 below.

4.3
Pedestrian volume Pedestrian surveys were conducted at 75m stretches. Pedestrian crossings taking place (in both directions) at 5 minute intervals were recorded separately on High Level Road, Old Road, Dehiwala Road, and Pamunuwa Road within the study area. This gave us a good insight of the pedestrian crossings taking place in the study area and a basis to design the proposed pedestrian crossings.

4.4
Accident data The police usually maintain daily accident records. It contains the date, time, location, nature of accident and elements involved. Three natures of accidents were categorized as; Fatal, Grievous, and Light. Data within four years (from 2007 onwards) was collected.

4.5
The traffic volume forecast Using the present traffic volumes and relevant growth factors obtained from RDA future traffic in the study area was computed. This helped to foresee the traffic demand in another 15 to 20 years from now. This in turn helps to decide the highway capacity at a suitable level of service for the predicting time period. Figure 4 indicates the peak hour traffic volumes that would be added to the High Level Road due to the Southern Expressway and Outer Circular Highway in year 2030 [4,5]. Morning peak hour flows were taken towards Colombo direction and evening peak hour flows were taken in the opposite direction.

Capacity analysis.
Road capacity checks were carried-out for the High Level Road, Old Road, Pamunuwa Road and Dehiwala Road using US highway capacity manual [7]. Level of services for each road segments were checked for existing traffic conditions. Initially capacities were checked for current traffic condition in above four roads. Then it will be continued for High Level Road and Old Road, considering both normal traffic and additional traffic from Southern Expressway and Outer Circular Highway in year 2030.

Design of road widths and introduction of additional lanes
From the above capacity analysis results, by considering impact of traffic from Southern Expressway and Outer Circular Highway, it was proposed to improve the study area roads by introducing suitable road widths and sufficient number of lanes to cope with the traffic needs at a meaningful level of service.

Level of service criteria
Level of service criteria for multilane and two lane highways are defined in terms of density [5]. Complete Level of Service (LOS) criteria are given in US highway capacity manual for 70mph, 60mph and 50mph design speed elements. That gives the average travel speed, the maximum service flow rate, Maximum Servoce Flow, for each level of service. The maximum service flow rates are stated in terms of rates of flow for the peak 15 min. Demand or forecasted volumes will be divided by the peak hour factor to reflect a maximum flow rate. High-level Road, Old Road and Dehiwala Road will be considered as multilane highways and Pamunuwa Road is the two lane highway. In this study, for capacity analysis both of the above mentioned criteria were used [5].

4.9
Capacity analysis of the Old Road (multilane highway) Old Road in Maharagama town area was considered as a multilane highway, and capacity checks were conducted as per US highway capacity manual (1985) [5]. Pedestrian crossing in front of the supermarket greatly affected the vehicular traffic on High Level Road and vehicular traffic from Maharagama to Dehiwala. Also large numbers of pedestrian were using this pedestrian crossing. Hence it was decided to design it as a signalized pedestrian crossing.

4.14
Check pedestrian crossing time for signalized pedestrian crossing When projected for a population growth rate of 1.4%, a zebra crossing will not be sufficient for the pedestrian volume in 2030 in front of the super market. It exceeds the allowable width of the zebra crossing. Therefore when considering pedestrian safety with vehicular growth and population growth, its better to propose a pelican crossing in front of the super market.

4.15
Analysis of accident data Accident data of four years (2007 to 2011) was collected. Data on date of accident, time, location, elements involved and nature of accident were obtained. Locations were selected from data which had more than three accidents (ie. any type, either fatal, grievous or light) within four years. Those were identified as high risk accident locations. The distribution of types of accidents is shown in Figure 5 and the collision diagram is shown in Figure 6. Identification of black spots As per accident data from police records it was able to identify eleven high risk accident locations; which had more than three accidents within four years in study area. Weightages were given to different types of accidents and calculated the total weightage of each identified black spot locations and ranked them. According to the gravity of accident category weightages of 5, 3 and 1 were assigned for Fatal, Grievous and Light respectively [3]. P = X + 3 × Y + 5 × Z, where X = total number of light injuries Y = total number of grievous injuries Z = total number of fatal injuries When total accident weightage was greater than 15 it was taken as a black spot. Calculated weightages for each location were plotted and is shown in Figure 7.  Five fatal accidents had occurred within four year period in this study area.
Most of the accidents were vehicle to vehicle and vehicle to pedestrian related.
Most cases of pedestrians involving accidents had happened due to haphazard crossing of roads.
Pamunuwa Road junction was the major area prone to accidents.
According to the above observations vehicle accidents in Maharagama area was not due to high speed driving of vehicles but due to congestion of moving vehicles and pedestrian movements. Most of the accidents occurring in this area is pedestrian involving accidents due to haphazard crossing of roads. Furthermore vehicle to vehicle accidents occurred at Boe tree junction, Clock tower junction, Pamunuwa Road junction and President's College junction with conflicting movements due to improper geometric design of above junctions. The walkways and carriageways need to be separated by a pedestrian protection fence at each junction, to avoid

Total weightage of accidents
Total weightage resort to the use of the roads which will increase the pedestrian's personal safety.

4.17
Traffic island design Dehiwala Road junction, Bo-tree junction, Pamunuwa Road junction and President's College junction were redesigned using the AUSTROADS vehicles and turning path templates. For this design arterial/collector was used for the intersection road type and also single unit truck bus was used as the design vehicle. Normally turning speed of townships was 20 km/h. But Pamunuwa and Dehiwala are pedestrian congested junctions. Therefore when designing islands for Pamunuwa and Dehiwala junctions 5-15 km/h turning speed was selected. Furthermore Botree and President's College junctions were adopted 0 -5 km/h turning speed due to geometry of them [8].

Improvement of roads in
Maharagama town area High Level Road and Old Road are major roads in Maharagama town area. They will be directly influenced by additional traffic from Kottawa interchange after implementation of the Southern Expressway and Outer Circular Highway. In this study Maharagama town area with main approach roads to the High Level Road and Old Road was only considered. Also traffic volume from above approach roads which are Dehiwala Road and Pamunuwa Road was considered for designing all the roads in this area in year 2030. According to the collected and observed data and analysis carried out, it was observed that High Level Road and Old Road are not in a satisfactory condition to accommodate the additional traffic from Southern Expressway and Outer Circular Highway once they are in operation. Through this study, checks were done to observe the road capacities with current traffic in year 2010 and additional traffic due to Southern Expressway and Outer Circular Highway in year 2030. According to these checks it was found that present road capacities will not be sufficient to cater even the normal traffic growth of traffic on High Level Road (without any contribution from new roads) in year 2030 to function at a satisfactory level of service. Therefore to cater to the normal traffic growth and additional traffic from two new highways at year 2030, Old Road and High Level Road had to be redesigned as multilane highways by introducing new lane widths, road widths and by adding reasonable number of lanes to maintain a level of service D during the peak flows. Although level of service D is not a satisfactory condition, since it was considered for peak hours in year 2030 (worst scenario) it was accepted for this study.
Both Dehiwala and Pamunuwa Roads are two directional roads in Maharagama town area. But for normal traffic growth by year 2030 they also will find it difficult to cater to the above traffic with suitable level of service. Road capacities were checked for Dehiwala and Pamunuwa Roads and also designed as two directional highways by introducing new lane widths, road widths and by adding new lanes to operate at level of service D during peak flows. Designed road widths and lanes were stated in Table B-3 in Appendix B.

5.2
Walkway shoulders and pedestrian safety Maharagama town area is a pedestrian congested area due to commercial buildings and wayside traders. The current walkway widths were utilized by unauthorized persons such as wayside traders and squatters. Therefore the walkway widths were reduced and as a result pedestrians tend to use the carriageway. Hence they lead to an unsafe situation. According to the US highway capacity manual all walkway shoulders in Maharagama town area was widened and also walkway shoulders and carriageways were separated by providing pedestrian safety fences at each junction. Designed walkway widths were stated in Table B-4 of Appendix B.

5.3
Pedestrian crossings and pedestrian safety Zebra crossings were redesigned to improve the level of service of the pedestrians and also all the crossings were checked to identify the current level of service. Road signs were introduced at each pedestrian crossing to enhance the pedestrian safety. But maximum pedestrian volume was observed at the zebra crossing in front of the supermarket, and it was not enough to provide suitable level of service for pedestrians. Also this crossing was adversely affecting the vehicular flow on High Level Road causing excessive delays. Therefore pedestrian signalized crossing was introduced at that location to minimize the interruption of vehicular flow and to enhance the safety of pedestrians who used this crossing.
Furthermore black spot locations were identified in study area and according to the weightages they were ranked. According to the accident analysis most of accidents occurred when pedestrians were physically crossing the roads. Therefore road signs were provided to inform the drivers about the locations of the pedestrian crossings. On the other hand most of the accidents occurred due to absence of lane markings. Therefore proper lane markings were provided for all roads in Maharagama town area. Furthermore traffic islands were designed for main junctions to avoid traffic conflicts and also improve the pedestrian safety.
Acquisition of land and other related activities which creates social problems are involved in the widening of all roads in Maharagama town area. Therefore Old Road and High Level Road were redesigned with 12ft lane widths with five lanes. Pamunuwa Road was designed as a multilane highway consisting of 3 lanes for each direction with 10ft lane widths. Dehiwala Road was designed as a multilane highway with 3 lanes for each direction with 12ft lane widths. Maximum width of zebra crossing was designed as 5m and other crossings were designed as 3m or 4m considering the relevant pedestrians volume.