Long distance car sensor.

[Um...Me123]

This is a complicated issue and I'm a beginner at electronics.  I can't explain everything now but I need a way to "see" a car where it can't be visually seen.  There is a limitted area I can put sensors, recievers etc. but I will try to make a diagram eventually.  For right now i just need to know my options for sencing a car in daylightand night (I know, just night would be easy)  This has to have a long range of how far away it can "see" the car and then needs something such as a led to notify of an oncomming car.  It's very hard to explain but I can explain later once I find out my options.
How do those things that you stick at the end of you driveway work?
An infared beam (straight accross the street) won't work because I cannot put anthing at the place where I need to sence the car soon enough.
Sorry if this is way to confusing!
Thanks!

[grsparks]

If you can cover the area with a wireless camera,  and feed the receiver into the
usb port of your computer with an adapter or into a video board, there is software available to monitor the image for movement.  The pc could take a snapshot and alert you with a tone.  I tried this trick on my driveway but the camera I selected had poor nite vision capabilities.  The software I found on the internet was shareware.

[Um...Me123]

Sorry I haven't replied lately.  Because they have to work at night the camera might not work because the infra-red won't cover enough distance. (I need several hundred feet of coverage.)  Plus that would be expensive and the Nebraska weather will wear away at camera even if it's weather proof.  Also it would be prone to theif.  We don't ever have eye contact witht he area where it would need to be.  (There arent any buildings for it to be attached to wither)  I'm at school right now so I'll take some pictures and make a diagram or something to explain the situation better when I get home)
Thanks guys.