This article examines the duration of 238 construction cases at three first instance courts in Belgium by composing a detailed timeline for each case. The results show that disputing parties account for 40 percent of overall duration, calendar delays and judges each for 23 percent. Despite the differences in overall duration between our three courts, the relative shares of disputing parties, judges, and legal experts are nearly identical. Furthermore, we combined our quantitative results with interviews of all judges involved in our dataset and an elaborated lawyer survey. Both the quantitative and qualitative results show that the level of activism of the judges involved significantly impacts the overall duration and efficient flow of proceedings. Our results suggest that judges do have the possibility to speed up proceedings, but given the prevalence of party autonomy in Belgium, a change in mindset of many judges is necessary to ensure the effectiveness of guidelines and procedural rules that aim at accelerating court procedures. ; Samantha Bielen would like to thank the Research Foundation Flanders for funding her postdoctoral mandate with grant number 12S3117N.