Persistent audible reminders can increase seat-belt use by as much as 34%, which is equal to the effectiveness of speed-limiting interlocks, according to a recent study from the Insurance Institute for Highway Safety.

IIHS researchers estimate that some 1,500 lives a year could be saved if all vehicles were equipped with persistent belt reminders.

The study assessed how drivers who are part-time seat belt users — and recently received a ticket for failure to buckle up — responded to four distinct technologies.

Using various vehicles, the study evaluated drivers' reactions to an audible reminder of three seven-second periods of chiming, a minute or more apart; a 100-second audible reminder; an indefinite audible reminder; and a speed-limiting interlock that restricted vehicle speed to 15 mph if either the driver or front passenger was unbelted.

While researchers anticipated the interlocks would rank as most effective in motivating drivers to buckle up, that wasn't the case.

Rather, the speed-limiting interlock, the indefinite audible reminder and the 100-second constant reminder all performed equally — increasing belt use by up to 34% compared with the intermittent audible reminder. The gear-shift interlock increased belt use 16% relative to the intermittent reminder.

The fact that persistent belt reminders are just as effective as interlocks is good news, according to the IIHS, as belt reminders are a viable and possibly preferable solution. 

For starters, drivers often circumvent interlocks by buckling the belt behind their back or sitting on it. Moreover, interlocks could prevent a motorist from operating a vehicle in an emergency or the limited vehicle function could increase crash risk by suddenly slowing the vehicle down.