Many of the crosswalks here in Spokane, Washington have countdown timers that count down to red, or rather to yellow, as it's green, yellow, red here in the states.
They are easily visible as you drive, without looking at your phone, which here will get you a ticket if the fuzz see you.
The only real difficulty is that percentage of drivers that use it to 'beat the light' rather than prepare to stop. But bad drivers are a universal problem.
And if you must watch your phone to be prepared to go at the green light, you're doing it wrong to begin with. You aren't paying attention to what is going on around you. Unless it's three a.m., you are quite unlikely to acquire everything that has changed since you took your eyes off the road in the few seconds the timer quits displaying before the actual change.
And before someone yell's "I can!" I call bullshit.
I have never once seen someone able to do it in the decade I taught commercial semi (articulated lorries?) truck drivers though I heard claims of this type and many more that were even more amazing.
Every. single one of those 'amazing multitaskers' failed, because every one with that mistaken belief in their heads have one thing in common. They practice what they preach and show everyone just how poorly this works.
And since it takes an exceptionally clean driving record to even get to be trained by me, I was training the top of the class compared to the driving public as a whole. And many of them still sucked.
The salvageable ones learned the Smith System and by and large became good, responsible drivers. There are always exceptions, but they don't generally last long once they are on their own.
Multitasking drivers equal good business for funeral homes.