I am working on a transportation web app and I am having a bit of a problem.

First, I want to be able to define a shipping corridor, say like I-95 between Baltimore MD and Richmond VA. And store what parameters I need to define this route.

Users will then use a web interface and can select various routes, in this case, I-95.

Vendors will be posting constantly changing pickup locations in the application database which have a shelf life of about 2 days. Some of these locations maybe along this route. I am storing the LAT and LONG for the specific location right now.

If any of these points ARE along or within 2 mile of the route (just off the highway basically - the ideal check would based on an actual highway exit but at this point anything would work), I want them to show up in my search results.

Any ideas or suggestions?