I took a defensive driving course at one time that was taught by a retired Texas DPS officer. He instructed us to NOT flash our lights at on-coming cars. Apparently some studies have shown that intoxicated drivers will actually instinctively steer toward the flashing lights. Texas DPS probably has to deal with more drunks than any other single law enforcement agency. That's enough to keep me away from one of those headlight modulators. Not to mention the fact that they are annoying.
