Saturday I was riding south down the highway pretty much all by myself on a three-lane-wide stretch of I-5 somewhere near Centralia, WA when I came upon an on ramp complete with a car entering the freeway. I was in the center lane, so I figured all was good to go with the merging car. I had my cruise control set on 65 and the car was doing about 60 as it entered the right lane a few car lengths in front of me. She stayed in the right lane until I was even with her back seat when she began to creep over to the left. As her tires crossed into my lane I touched my horn button and activated one of these Ear Cannon Air Horn :: Aerostich/RiderWearHouse Motorcycle Jackets, Suits, Clothing, & Gear She immediately turned her steering wheel to the right, which pointed her car at the wall. She knew that was bad so she turned it back to the left, which brought her back my way. All her turning had slowed her down, so when she crossed back into my lane again she was just behind me. I watched her in my mirror as her car did its best to copy a bike in a tank slapper, all the while going slower and slower. She never turned her head to look, so I don't know if she ever even looked in her mirrors, but I think next time someone does that to me I won't get offended and try to defend my space with the horn. Next time I think I'll grab a hand full of throttle as I move to the left side of the lane and not scare some oblivious drive until I am out of range of their bumpers and fenders. I wonder if she peed her pants?