1 INTRODUCTION
The transportation network is of critical importance for supporting the mobility and accessibility needs of the nation as well as ensuring its economic vitality. The importance of reliable and effective transportation systems as essential means to quick response in case of emergencies to ensure safe, continuous movement of people and goods as well as support response and recovery operations can not be overemphasized (Sisiopiku 2007). In order to maximize road network efficiency, improve traffic conditions for the traveling public, and overcome problems such as increasing levels of traffic volumes in both normal and emergency situations, transportation authorities continuously make changes to the existing traffic patterns of streets and roads by performing line closures, adding provision of bus lanes and High Occupancy Vehicle (HOV) lanes, lane reversals, and implementing several vehicle turn rules. During a typical road construction project, intersection designs and traffic signalizations may be temporarily or permanently changed by city planning officials in order to optimize the flow of traffic and minimize time lost in traffic discharge (Ceylan and Bell 2004). In complex and dense urban areas with relatively higher traffic flow, the negative effects from an inefficient traffic pattern design change are more pronounced which makes the optimization and design process even more critical and complicated (Mirchandani and Head 2001). The large scale impacts of such changes on traffic pattern, if not studied well beforehand, can add up to the existing problems and even make the situation worse.