Stoplights.
To prevent all the cars crashing into each other at junctions.
the sirens tell people that a car is coming also it sends a signal to stoplights for a go.
"How many stoplights are on Main Street, if you know?"
Yes
yes
yes
first cars got speakers in 1983
By Garrett Morgan 1923. Oh and I'm the Boss
cars were first invented in the late 19th century
Ther wasn't a battery in the first cars.
what year did the first cars arrive on the prairies
It is a switch on the brake pedal which sends current to the stoplights in the rear.