Thank you for this reference. Table 37 on Page 39 is most relevant to this accident. Interestingly regular gates appear to have fewer accidents than 4 quad gates, after adjusting for number of trains and vehicle traffic. Unfortunately use of traffic signals, wigwags, and bells were put in a single class so we don't know if using traffic signals is more or less effective than gates. (As a class the traffic signals/wigwag/bells class had more accidents.)