The decision

Here's the rule, and it's one sentence. The phone is out of reach before the engine starts, and anything with a screen happens with the handbrake on.

That's both halves. The first half removes the peek on the move and at the lights, because the phone isn't where the hand goes. The second half covers the map, the music and the message you're going to send, by giving them a place, which is the kerb. There's no judgement in it about what's safe or urgent or only a glance. Those are the beliefs from chapters 3 to 14, and the rule's whole design is that none of them gets asked.

Peter Gollwitzer and Paschal Sheeran, in a meta-analysis of when-then plans that earlier books in this series have leaned on, found that a specific plan of the form "when this happens, I'll do that" reliably helps people act on an intention they already hold, and the effect is medium to large. The rule needs three of them. When I sit in the driver's seat, then the phone goes in the glovebox before the seat belt. When the phone buzzes in the glovebox, then I say "later" out loud and keep driving. When I need the map or the phone on the move, then I pull into the next safe place and put the handbrake on. Say them once, write them if it helps, and keep them exactly that plain.

What to expect, and this is my expectation not a finding. The first week the hand goes to the cupholder at every red light and finds nothing, and the itch is loud, and you'll feel slightly ridiculous. The second week the hand goes less. Somewhere in the first month the drive gets quiet in the way chapter 17 described, and the glovebox becomes where the phone lives without your deciding it each time. Phillippa Lally and colleagues followed ninety-six volunteers building a daily habit and found automaticity grew over weeks and varied a lot between people, so I won't give you a number of days. What I'll say is that this habit has an advantage most don't. The car is the same every day, the seat is the same, and the glovebox is in the same place. Cues don't get much more reliable.

Two things to say out loud, once, before you start. The standing message to the four people, from chapter 19. And to whoever's usually in the car with you, "the phone's going in the glovebox from now on, and if I reach for it, say so". That last one recruits the norm from chapter 14 onto your side.

Then start. The next drive, not Monday.