Assess the Risk of the Crossing
How likely is it that I am going to be surprised by an approaching vehicle that could reach me during my crossing?
The probability that an unexpected vehicle could reach you when you cross in a Situation of Uncertainty depends on two things:
Likelihood of being surprised will vary!
1. Traffic volume (how much traffic is there?)
2. Warning times (How much warning do you have that vehicles are approaching?)
The fewer vehicles there are traveling on that street, the less likely there is an undetected vehicle coming when you start to cross.
For example if there are only 2-3 vehicles a day on that street, it is unlikely that as you start to cross, one of those vehicles is approaching just beyond your ability to hear/(see) it.
But if there are dozens of vehicles passing every minute, whenever there is a break in traffic and you hear/(see) nothing coming, it is much more likely that there is an approaching vehicle that is just beyond your ability to hear/(see) it.
The more warning that you have about the approaching vehicles, the less likely there is an undetected vehicle coming when you start to cross.
You are concerned about the drivers who are close enough to be able to reach you but not close enough for you to be able to detect them.
So the further that you can detect them, the less likely there is one that could reach you but you can't detect it.
For example, let's assume you need 8 seconds to cross.
It is much more likely that you'll be surprised by approaching vehicles if you can't hear them until they are only one second away than it would be if you can hear all of them at least 6 seconds away.
Of course, since the volume of traffic and its warning times can vary greatly from one time to another at any given crossing,
so will the likelihood of being surprised by an approaching vehicle.