The standard does not call out specific tasks or situations where Performance Class 3 should be used rather than Class 2. Non-mandatory Appendix C of the standard covers suggested type and class guidelines and scenarios. While specific duties are discussed under types, performance class selection between 2 and 3 is not as clear. The appendix states that the guidelines and scenarios are intended to serve as an assessment tool only. Certain specific conditions such as “atmospherics, sight/stop distances, training, regulations, proximity and others must be taken into account in any final hazard/safety assessment. Vehicle speed should not be considered in isolation to these variables.”