This question is a bit Stata-related, a bit general panel data analysis-related. I've got a panel data set for a set of road segments that looks like this:
Road ID Day Time Variable1 Variable 2
1 Mon 9am 56 8
1 Mon 10am 47 17
1 Tue 9am 55 43
1 Tue 10am 53 58
2 Mon 9am 78 23
2 Mon 10am 17 7
2 Tue 9am 74 45
2 Tue 10am 19 32
and so on. I would like to set this up as a panel data model, with Variable1 being a function of Variable2 + error term. My confusion is in how to define the data structure. In this case, my panel ID variable is "Road ID", and I would like my time variable to be "Time". But how do I handle the "Day" variable?

What I would like to do is to have Stata recognize that each RoadID/Time combo has multiple observations. For my particular data set, it can safely be assumed that there is no heterogeneity across days, only across Road ID and time. Is this set up possible?