If the Avenue assignment has included a warm-up period, the user should choose to use the warm start option for more accurate results in early time periods. When using this option, Analyst Drive will generate warm-up period route choice and OD matrices while processing the packet log file. Analyst Drive uses these to generate a warm-up period volume which is used to adjust the observed counts, as described in Chapter 2, “Model and Numerical Method.” Note that when doing a warm start, the report file generated at the program’s conclusion will contain the adjusted count values, and not those input via the count file. If the user desires, they may include their own warm-up period matrix by placing it in the first tab of the matrix file and checking the WARMAT option. In this scenario, Analyst Drive will use the user-supplied warm-up period matrix instead of pulling one from the packet log file.