We investigated how an increase in straylight affects the driving capacity of young, healthy volunteers between the ages of 20 and 40 years (i.e., people without cataract) in various real‐life driving circumstances using a driving simulator. This simulator allowed us to assess driving behaviour in a controlled, repeatable environment without risk to life or property, while providing a large set of parameters (speed, brake performance, deceleration, collisions, standard deviation of the lateral lane position, (SDLP), headway distance, etc.). The simulator used a fixed‐base setup with a force‐feedback steering wheel, an instrumented dashboard, brake, and accelerator pedals and with a 135° field of view. Participants had to drive along a certain course with of 6 traffic situations (e.g., crossing pedestrian, obstacle on the way, etc…) while wearing their own spectacle correction, both in the presence of a glare source and without. Next this was repeated while wearing a Tiffen Black Pro Mist (BPM) filter in front of their eyes and a glare source. These filters approximate the optical characteristics of cataract fairly well, where BPM 1 mimics simulates early cataract (which often prompts people to stop driving at night) and BPM 2 simulates serious straylight hindrance. Straylight was measured with the van den Berg straylight meter (C‐Quant). The results showed that increased straylight significant alters driving behaviour, such as a decrease in mean, maximum and minimum speed. The detection time and reaction time to an obstacle on the road was significantly longer with increased straylight. Consequently, straylight is an important factor in traffic safety driving conditions, causing altered driving behaviour and increasing collision risk in certain traffic situations.