Existing volume considerations are discussed previously in this chapter, under

Section 3.2

. These considerations include traffic data factors, seasonal factors, historical factors, peak hour/period selection, disruptive events, traffic balancing, post processing, and validation.

Existing data can be obtained from various sources, including the TxDOT STARS database, MPO counts, the statewide planning map, or big data. For more information on data collection, see

Chapter 2.