White vic with laser or radar along I-635 feeder, measuring eastbound cars that exit from I-635, and drive feeder to Olympus Drive or MacArthur Blvd (1.9 miles ahead). Cars that enter feeder from Beltline Rd can easily see car waiting at the “road closed” stub from a 0.3 mile distance, but cars on interstate exit ramp will first go over small hillcrest before having full visual. If you park at the stub you can see cars exit I-635, disapear for a short moment and then popup in full view after the crest. Line of sight from stub to crest is 200 yards. Interstate speed 60mph, feeder has 55 mile posted at the spot where the Dont Cross White Double Lines begins (dbl white separates exit ramp traffic from 2 other lanes).