Over-lockout pushes drivers onto their phones

What it is

When the in-vehicle system locks the function someone meant to use, the intention does not cancel. The phone does the same job instead. That is a side effect of lockout, not the whole topic of phones in cars. A phone is not under this vehicle’s speed lock, is not guaranteed a mount in the sight line, and often occupies a hand. Visual-manual demand is usually higher than the in-car path that was locked. A lock that shuts a lower-risk cabin method is a push toward a higher-risk one. This entry is only that substitution. It is not how phones should be designed, and not whether lockouts should be cut by risk or by category.

Why it happens

The intention remains: search a place, answer one line, change a playlist. Greying a button and posting “do this parked” does not close the intention. It closes the cabin path. The phone is already on the body and not governed by this car. Reaching for it, unlocking, finding the app, typing—eyes off the road, a hand off the wheel, often longer than tapping a favourite on the stack. The more thoroughly a lock is applied “for safety,” the more the only open road is the least governed device. Some drivers type the destination into phone navigation before they start and prop the phone on the wheel. The lock did not remove the task. It moved the task off a surface that could still be designed.

Studying it

In naturalistic or instrumented-vehicle observation, when a class of in-car function is locked, code pick-up, looks-to-phone, and phone manipulation, and compare with unlocked conditions or with a low-demand in-car path. Interviews can ask “what do you do when it locks,” but the object to code is where the hands and eyes went.

Independent variables: the function locked, available via a low-demand path, or fully open; phone in a mount or not. Dependent variables: phone pick-ups and duration, glances to the phone, hands-off, whether the phone is held up into the sight line.

Labs that ban phones will not show the side effect, and lockout will look clean. Field studies that only count “was the IVIS used” will score demand that already fled to the phone as a successful lock.

Where it stops holding

No phone, a dead battery, or a policy that kills cabin signal removes this substitute, and people may actually defer. A passenger operating the phone moves the risk off the driver; the mechanism changes. Under high automation the immediate cost of looking at a phone drops, and the side effect shifts from “reaching while driving” to “still holding it at takeover.” Some markets legally require a locked keyboard; the side effect remains. Compliance is not evidence that no one will use a phone.

Applying it

• When locking a high-demand path, leave an obvious low-demand in-car path: a favourite, a recent destination, voice, a short press on the wheel, so the intention need not leave the vehicle system.
• Lock copy should not only say “park first.” It should name the one action that is available now. A grey button with no substitute is an invitation to the pocket.
• Verify on real or near-real trips with that function locked, and watch for a turn to the phone. If it appears, restore a low-demand cabin path before tightening the lock another notch.

Related

• Within the group: K6.06.1 Lockouts should follow distraction risk, not feature category · K6.06.3 Passenger use is hard to separate from the driver’s
• Adjacent: K6.01 Types of Driver Distraction · K6.10 In-car Voice and Gesture
• Search terms: lockout workaround · phone substitution · unintended consequence