Egyptian roads are rapidly increasing in traffic demand during the last few years. So; it becomes necessary to allocate substantial resources to construct new roadways as well as maintaining the existing infrastructure. Pavement maintenance usually requires closing some lanes of highway; this may cause disruptions to normal traffic flow. These roadway sections with reduced width may cause speed reductions, increased in travel time cost (TTC) and increased in vehicle operation cost (VOC).The aim of this study is to determine the optimal number of closed lanesto achieve: Suitable operating speed (OS) and most reduction in national income loss, TTC and VOC at work zones.This study determined work zone configuration, traffic data, vehicle data and road data for most cases work zones at eight, six and four lane-divided highway to evaluate OS, loss in national income, TTC and VOC with the aid of world bank software (HDM-4).The results obtained from this software are verifying against some actual data observed in the field. In order to achieve verifying, a framework for data collection was designed. This framework includes field investigation at Cairo ring road, field data from previous study and data collection form.The findings of this study recommendedVOC decreases with increasing number of closed lane if the value of OS decreases from (free speed to 50 kph). VOC increases with increasing number of closed lane if the value of OS decreases from (50 kph to jam speed). TTC increases andOS decreases with increasing number of closed lane. VOC increases, TTC decreases and OS increases with increasing the speed limit for highway. No pronounced difference in OS value, before and at work zone, between measured speed in field and calculated speed by HDM-4 software.