Out of reach
The method has three parts and this is the first. It's the one that does most of the work, and it's the least dramatic. The phone goes somewhere your hand can't get to it at a red light.
Where it goes. The glovebox, if you have one you can reach from the driver's seat while parked and not while driving. The bag on the back seat. The boot, if you're the kind of person who'll otherwise reach behind you. The pocket of the coat you've put on the back seat. Anywhere that would require you to undo your seat belt or turn round to reach it. Not the cupholder. Not the passenger seat. Not face down on the passenger seat, which is the compromise everyone tries first and which lasts until the second buzz.
Why not face down. Because the peek isn't a decision, which was chapter 12. A phone within reach is a phone you'll reach for when it buzzes, and turning it over only means you'll turn it back. The whole point of out of reach is that the itch arrives and finds nothing to do. The rule needs to be something your hand runs into, not something your judgement has to win.
The drive setting. Most phones now have a setting that detects driving and silences notifications, and many can send an automatic reply saying you're driving and will see the message later. Turn it on. It's not a substitute for out of reach, because a phone that isn't buzzing in the cupholder is still a phone in the cupholder, and the itch arrives without a buzz often enough. But it removes most of the buzzes, and it does the standing message for you, which chapter 19 is about. I'm not naming any phone or setting because they change. Yours has one, and the search terms are driving and do not disturb.
The two-call rule. The drive setting usually lets a repeated call through, or can be set to. That's the emergency channel. Tell the four people who might genuinely need you that if it's urgent they should ring twice, and the phone will ring. Then the urgent belief from chapter 11 has an answer that isn't the peek.
Before the engine. The phone goes out of reach before the engine starts, not after the first buzz. It's the last thing before the seat belt. Once the car's moving, out of reach means stopping, and you won't stop, so the order matters.
That's it. It's almost embarrassingly small, and it's the whole method. The next two chapters are what to do about the people who expect replies and the things on the phone you genuinely need while driving.