This summer, we're driving to Chicago with the kids for a week. We're going to be staying in Alsip (my wife's company is headquartered there) but we'll want at least a day or two sightseeing in town. And obviously I don't want to have to deal with downtown traffic and parking, so I'm looking for somewhere to park and ride.

To my shock, it looks like the L has a daily parking lot at Midway Airport (on West 59th St), which appears to cost only $4 (as opposed to $17 or more in the terminal garage). And the pictures I can find of the lot on Google seem to show that although it's busy it isn't crammed full.

So... I'm wondering: what's the catch? Why wouldn't everyone park there if they're going to be there more than an hour but less than 12 hours? (OK, it's a tad further from the terminal, but not that bad.) Is there something I'm missing?

Oh, and are Google's pictures misleading? Does the lot fill up early in the morning? Is there somewhere better to park given that we're coming in from the Cicero/294 interchange?