Defence of dissertation in the field of spatial planning and transportation engineering Sanaz Bozorg, M.Sc. (Eng)

The impact on driver visual performance during darkness under varying artificial lighting levels, traffic and road surface conditions

The public examination of the doctoral dissertation of Sanaz Bozorg , M.Sc. (Eng), will be held on 16 August 2019 at 12.00 at Aalto University School of Engineering, hall F239a, Otakaari 3. The title of the dissertation The effect of different road lighting levels on drivers’ visual performance under various conditions. The field of the dissertation is spatial planning and transportation engineering (Transportation and Highway Engineering, Lighting, Visual Performance). 

Besides other frequent causes of accidents such as alcohol or drug use, fatigue, etc, limited nighttime visibility is one of the important parameters in traffic safety that requires attention. Although introducing road lighting can mitigate the amount and severity of accidents, energy usage and related costs of road lighting are the driving forces for more efficient road lighting technologies. It is therefore important to consider drivers’ visibility before implementing any changes. The aim of this dissertation is to provide information about the combined effect of differing brightness of road lighting in the presence of car headlights under varying road surface conditions on a drivers’ visual performance. The results can be used in the development of intelligent road lighting practices.The results of this study indicated in the presence of car headlights, with no glare from oncoming cars, headlights alone, or combined with a low lighting level, provided better visibility performance than when combined with full lighting intensity. The effect of different road lighting levels was not monotonic, reducing road lighting shifted the contrast from positive to negative polarity or vice versa and made the contrast approach zero in some conditions. Therefore, road lighting should be lowered to a level that does not neutralize the effect of car headlights. This result supports the feasibility of reducing road lighting level under different road surface conditions. In the presence of glare from an oncoming car, higher road lighting level provided better visibility than lower lighting levels, but the effect was not statistically significant.

Doctoral candidate Sanaz, Bozorg, M.Sc. (Eng) in Sustainable Technology

Opponent Professor Ronald B. Gibbons, Virginia Tech Transportation Institute, the United States of America

Supervisor Professor Tapio Luttinen, Aalto University School of Engineering, Built Environment Department

Eletronic dissertation http://urn.fi/URN:ISBN:978-952-60-8644-6