Around 1995 the Massachusetts driver's manual said something like "Only use the horn in an emergency" or "Only use the horn to avoid an accident." I've found t

Around 1995 the Massachusetts driver's manual said something like "Only use the horn in an emergency" or "Only use the horn to avoid an accident." I've found that most Massachusetts drivers abide by that. > and car in front of you has not begun moving within 20ms No... It's more like 2-3 seconds. But you THINK it's 20ms because you're not paying attention.