Petrol and Disel vehicles tend to make huge Engine sound. That means you can use your ear to determine whether there is a vehicle coming from the distance where you may not see, especially during heavy fog or during crossing road inside a inner road.
Lets be honest here, 99.99% people only follow good practices when crossing road in a major highway. Most people dont even look behind when crossing in small roads away from the highway.
I was walking today and an electric scooter just speeded up and passed me by. If it were a petrol engine I would hear it coming even when I am not directly looking.
The regulators have been working on this problem for awhile.
My 2015 Volt has a pedestrian horn that you activate on the stalk.
My Tesla sounds like a UFO when backing up. The Mach-E sounds like a bulldozer when backing up.