In an ideal world there would be no crashes in traffic. Unfortunately the real world is far from ideal and over 20,000 people get injured in a crash in the Netherlands each year. Around 46,7% of these registered crashes, take place at intersections. To decrease the chance and number of conflicts, and therefore the chance of crashes, many intersections are controlled by traffic signal control, but these will only have effect when the signals are obeyed. In almost all traffic signal control systems the motorised streams are prioritised, because of the space and time needed for cars to cross the intersection. Therefore cyclists, who can cross in high numbers in a short time, have longer waiting times compared to motorized streams. As a result cyclists are possibly more likely to ignore the traffic lights and cross when seems safe to them. When they cross during the phase where the light is turned red, this is called red light running. The purpose of the report is to give insight in the percentage of the red light running by cyclists in the Netherlands, the influence factors and the consequences for traffic safety. Through literature review an inventory of the different factors that influence red light running is made. The characteristics found that increased the percentage of red light running were: Male cyclists, young adults, experienced cyclists, bad weather, long waiting times, reduced credibility/low conflicting traffic flow, short crossing distance, herding (when there are other people violating the red light they are more likely to also violate the red light) and a low percentage of trucks and busses. Though most literature was over 25 years old and thus was not recent enough to form hypotheses. Thus the study got a descriptive and explanatory nature. With the help of video observations on 5 different intersections, factors found in literature were analysed. The overall red light running was 27.4%. Factors that were found influencing red light running are: - Gender: Men violated the red light 1.32 times more than women. - Age: Young cyclist have a higher percentage of red light running, 1.63 times higher than adults and 1.78 time higher than elderly cyclists. - Crossing distance: A longer crossing distance decreases the red light running - Flow of the motorized streams: more traffic on the conflicting motorized streams lead to less red light running. The vehicle composition of the conflicting stream seems to have an effect on the red light running. However, the number of observations for these factors was too low to statistically test them. Therefore further research, with observation of more intersections, is necessary. The other factors did not have an effect or the effect seen was not statistically significant. It is recommended to do further research on the factors that have an influence on the red light running. The number of the observations, number of intersections or number of cyclists crossing in this descriptive research are too low to conclude without a doubt the effect of these factors.