[derobert]

Unfortunately, high beams also risk blinding oncoming traffic, potentially causing a collision.

In addition, I wonder if the blinking would be distracting, calling attention away from the problem (at least when the horn is being used as intended, not just by someone complaining about slow traffic).

[gomox]

Can you describe such a situation? As far as my thought process goes, the horn is meant to attract attention, and lights only help that purpose.

If you are driving on a dark road with traffic coming on the opposite lane (the only situation I can conceive where high beam blinding is a problem), why would you sit on the horn for more than 1/2 a second?

[jrootabega]

It could do a quick pulse at night, and a longer one during the day.