Avoiding the black hole effect when approaching the entrance zone of a tunnel in day time is the main concern of the tunnel lighting designer. For achieving a correct balance of luminances in the field of view of any observer at the entrance of a tunnel, it is necessary to study of the daylight environment outside this tunnel. Several methods exist. They diverges on the recommended lighting levels at the tunnel entrance. This may lead to excessive oversizing or in some cases, depending of the tunnel's environment, to inappropriate solutions. The normative methods all consider static ‘worst case' outside conditions. The aim of this study is to explore the daylight variations at the tunnel entrance by using dynamic simulation software. This will enable to assess the actual predetermination methods for designing a lighting scheme at tunnel's entrance according to more realistic conditions. It should also help to define different artificial lighting scenarios to achieve important energy savings and safeguard the visual comfort.