Why is he driving by my house?

Ok, so this guy a was dating, who I have not been out with in over 2mos, but still talk to maybe once a week, is driving by my house, yes he does live on my street but there are 2 other shorter, faster alternate routes he can take to go to work etc, this is when he drives by in the morning, right at the exact time I usually leave for work, this morning he drove by but I was running late so I was not in the driveway like normal, anyhow why is he driving by? He told me last Friday he would call this week, hasn't yet, but he's driving by? Also this is after I told him I was interested and would to explore the relationship further, it just doesn't make sense, he doesn't call, doesn't respond to what I told him, yet he's driving by? What is that about? Guys what up with the drive bys?