Safety belt use on U.S. roads approaches 80 percent, up from fewer than 20 percent in the early 1970s. But what about the holdouts, those who are hard to convince to buckle up? Ford was first among automakers to try to reach these motorists by going beyond the safety belt reminder systems required in all passenger vehicles. Now, spurred by the National Highway Traffic Safety Administration (NHTSA), virtually every automaker is going beyond the sound-and-light warning that's required if a driver's safety belt isn't fastened. This warning is brief. NHTSA isn't allowed to require any sound persisting longer than eight seconds.
"It's easy to ignore such a brief warning," says Institute chief scientist Allan Williams, "and under current federal law it isn't possible for NHTSA to require longer warnings that might prove more effective."
But automakers may install any kind of reminder they want. The first voluntary system, a chime-and-light sequence that persists in intervals for up to five minutes if a driver doesn't buckle up, was introduced in 2000 model Fords.
"Call it benevolent nagging. The chime Ford uses isn't unpleasant, and it keeps on reminding you for five minutes. When we evaluated this system we found it produces a modest but important increase in belt use," Williams says (see "Safety belt reminder system in late-model Fords boosts buckle-up rate," Feb. 9, 2002).
Based in part on the Institute's evaluation of Ford's reminder system, NHTSA Administrator Jeffrey Runge urged all automakers in February 2002 to "consider voluntarily adding inexpensive, but effective, buckle up reminder systems" and to do so "as quickly as possible." Now reminders are in most 2004 model passenger vehicles.
All reminders aren't alike
There's variation among automakers in terms of the kinds of belt reminders they're using and how many models they're equipping. Audi, Ford, Hyundai, Porsche, and Volkswagen say they're putting reminders with intermittent lights and chimes in all 2004 passenger vehicles. Other manufacturers report lesser percentages. The loudness, urgency, sequence, and duration of the lights and chimes vary somewhat. General Motors adds a text message instructing drivers to buckle up.
Less elaborate reminders are in Infiniti, Lexus, Nissan, Saab, Scion, and Toyota models (except Toyota Prius). A light stays on, but no chime persists beyond eight seconds (the Prius does have a persistent chime).
In contrast, enhanced reminders aren't in any Hummers or models made by Isuzu, Land Rover, Mini, Mercedes, Subaru, or Volvo.
"Lights-only reminders haven't been evaluated yet, but the systems with audible warnings are almost certainly going to be more effective because a repeating chime or other sound is harder to ignore," Williams says.
Idea of enhanced reminders isn't new
In the early 1970s when only about 20 percent of drivers were buckling up, NHTSA tried several approaches to improve the situation. First there was a mandatory 60-second buzzer light in cars without automatic restraints (virtually no cars back then had such restraints). Starting with 1974 models, cars without automatic restraints couldn't be started if front-seat occupants weren't belted.
The buzzer-light reminder wasn't effective, Institute research found, but ignition interlocks did work. A separate Institute study found 59 percent of drivers using their belts in cars with interlocks, while the use rate was only 28 percent in cars with buzzer lights.
The problem was that many motorists didn't like interlocks. Public outcry against them led Congress to prohibit NHTSA from requiring them. Congress also told the agency it couldn't require any audible signal exceeding eight seconds.
"Nowadays motorists apparently don't object so much to being reminded. Maybe interlocks still wouldn't be accepted, but reminders of the type Ford pioneered seem to be okay," Williams says. The Institute surveyed Ford owners, most of whom said they like their reminders. Almost half said they buckle up more often because they're being reminded (see "Ford drivers say they like being reminded to buckle up," June 16, 2003).
Belt reminders in Europe, too
No requirement forces automakers to equip cars in the European Union with any kind of reminder (Sweden does require them). Although belt use rates exceed 90 percent in many European countries, reminders still are needed because use rates in serious crashes are lower. And now there's a powerful incentive to install reminders because doing so can boost a vehicle's consumer safety rating.
The European New Car Assessment Program rates passenger vehicles based primarily on performance in front and side crash tests. Since 2002 points may be added to a vehicle's crash test score for a belt reminder. The score then is translated into a star rating. To get the extra points, an audible reminder has to come on when a vehicle reaches a specified speed for a short distance and stay on for at least 90 seconds or until the driver buckles up.
The addition of reminders meeting these criteria has enhanced the star ratings of the Mercedes C class, BMW X5, Peugot 807, Saab 9-5, and Volkswagen Touran (four to five stars, the highest rating). The Jeep Liberty's rating was bumped from three to four stars.
Some automakers are exploring or using more elaborate systems. Saab, for example, tested one that gets louder and more persistent with increases in speed and distance since the vehicle was started. A similar system is in some Volvos sold in Europe.
National Academy of Sciences weighs in
Responding to a request from the U.S. Congress, a committee of the National Academy of Sciences has surveyed developments in both the United States and Europe and issued a set of findings and policy recommendations about reminder systems. The first finding is that the reminders of four to eight seconds that are required in the U.S. market have "proved ineffective." Other approaches should be pursued to increase belt use "without being overly intrusive."
In the short run NHTSA should "encourage the industry to develop and deploy" reminders similar to Ford's, the committee recommended, so every new vehicle has "as standard equipment an enhanced belt reminder system for front-seat occupants with an audible warning and visual indicator that are not easily disconnected." NHTSA should speed the installation of reminders in rear as well as front seats. In the longer run Congress should change the statutes that prohibit NHTSA from requiring reminders lasting more than eight seconds. A proposal to do this is before Congress.
The committee didn't call for Congress to lift the prohibition on requiring ignition interlocks but did say entertainment interlocks might be an option. These would keep unbelted drivers from listening to the radio, for example, or playing CDs.
Williams, who served on the committee, says "the options are wide. Next is to find out how effective the various types of reminders are in increasing belt use, which ones work best, and which might not work at all. This will tell us where to go with the technology."