This study demonstrates possible energy-saving effect in case longitudinal control method based on local traffic states for energy conservation is used. If eco-driving is realized using longitudinal control for energy conservation, the control needs to observe various traffic states' information and reduce wasteful acceleration and deceleration. This study reports simulation evaluations of possible energy-saving effect using an algorithm that uses an idealized velocity pattern based on information such as Vehicles and signals, and optimal control for longitudinal using the eco-driving pattern.