A separate button that honks not only the stock vehicle horn but also at least three others of different frequencies, patterns and duration, giving the impression that everyone in the line of cars would like the lead driver to put their phone away and get moving.-- whatrock, Nov 29 2020 This would work. You can never tell which car is blowing its horn anyway. [+]-- doctorremulac3, Nov 29 2020 The type of air horn installed on EMD locomotives is useful for gaining the attention of less alert drivers and encouraging them to "move along" although the mild side-effect of bleeding from the ears can be unpopular.-- 8th of 7, Nov 29 2020 Well, we certainly wouldn't go that far. Would we?-- whatrock, Nov 30 2020 + I would definitely use this!-- xandram, Nov 30 2020 Could have a forward facing screen mounted inside the rear window, which plays video of a line of cars, flashing headlamps and angrily gesticulaing drivers-- pocmloc, Nov 30 2020 [+] Excellent. And relatively easy to engineer, 3-4 extra horns and some simple delay/pulse circuits would be quite easy. Much more could be accomplished with a microcontroller, whole different moods could be conveyed - anger, rage, aggressive tedium.-- bs0u0155, Nov 30 2020 Great, just what I need, when I'm late, stressed or being especially hypocritical.-- wjt, Dec 05 2020 random, halfbakery