Think the value depends entirely on what kind of end users see it. Most parks will have their own names and websites built around that name, and it seems a stronger interest would be from anyone with business online to do with parking links/pages. Even an info site or blog about parking/monetization might get you some traffic and possible adsense income. Maybe a guide/review site of all the parking companies you can find?
Still a lot of decent keywords with 'co' on the end, and there are a lot of variations of parking, although you have the shortest.
I think you'd only get in the med - hi xx range from a reseller, but in the low - med xxx from an end user who really wanted to use it.