Traffic Analysis and Environment Impact Assessment- Case Study of N-5 Corridor in Rawalpindi City

Abstract

The revamped Grand Trunk road in Pakistan stretches from Torkham to Karachi spanning a distance of 1756 km is still pretty much the heart and soul of country’s road network. A segment of the highway runs its course through the bustling city of Rawalpindi, an embodiment of the city traffic’s backbone. This particular segment of the highway forms linkages between the city of Rawalpindi and Motorways M-1, M-2 and to the highways of KP and south Punjab. These interconnections make the highway segment subjected to some significant traffic congestion along its length compounded by motorization and its rising use, which have been a major influence in the increased mobility of people, goods and services, and the consequent development and economic progress. While these phenomena have brought immeasurable benefits, it has not been without deleterious effects. Apart from the constant congestion problems the segment also faces some key technical issues which hinder in the progression of smooth traffic flow throughout this portion of the corridor. These problems can be categorized according to traffic flow parameters and Environmental Impact variables such as CO and NOx emissions. The traffic flow parameters that were imperative for the successful completion of this study are Level of Service (LOS), Traffic progression in terms of measuring delays and Intersection Capacity utilization among others. Delays due to increased travel times, excessive noise, deteriorating quality of air and general inconvenience for the users traversing the corridor suggests a chance for some major overhauling of the corridor to assist user convenience and comfort. Hence the objectives of this study have been formulated bearing strictly in mind the ensuing difficulties mentioned above that the road users face on a constant basis while traversing the corridor. These include the identification of measures to mitigate the current predicaments of congestion along the corridor, less than favorable traffic progression, and an unacceptable level of delays along with the environmental ordeals translated by emissions and noise emanating from the vehicles. Moreover isolated improvements along the chosen corridor have only made the upstream/downstream traffic flow conditions a little less optimum, hence an amiable solution to this problem is also sought. The scope of the project is limited to the corridor from Golra intersection on N5 to GHQ intersection about 14 km further down the corridor amongst the heart of the city. The site selection of the study stood out on itself being one of the busiest corridors of the city and serving freight movement in tandem with fulfilling the CBD’s passenger traffic demands. On-field readings included manual counts performed by the syndicate members by tally and Jamar Counters, signal timings and link lengths determinations formed the basic inputs that were utilized by the analysis software SYNCHRO for outputs such as LOS, ICU, travel delays at each intersection and Volume to capacity ratios. The analysis performed by the software was not limited to only existing/current scenarios but was broadened out to include future projected values for improved as well as unchanged scenarios. It also included values for CO and NOx emissions in addition to queue lengths and fuel used that enabled a comparison to be illustrated figuring out the impacts on the environment. The improved scenarios drawn up included lane width expansions where possible to suggesting traffic management plans where the geometry and the proximity of the built-up area forced no grade separation to be performed and the coordination of traffic signals that were in close vicinity such that coordination limitations were fulfilled. Grade separation was also envisaged on the Golra intersection as the geometry of the intersection was feasible for the construction of such structure. The plans aimed at smoother traffic progression and acceptable LOS’s by reducing delays, as well as lowering fuel consumption which would in turn reduce the harmful emissions into the environ minimizing the impact this road segment will have on the environ in general. These plans, if implemented and led to fruition by the concerned authorities would provide road users with a general peace of mind associated with a smoother traffic flow, reduced emissions and minimal bottlenecks and a corridor convenient as well as economical to traverse.