asingle one of the 24 small two-door cars tested this yearperformed aswellas the
best car a decade ago. Even the best new cars,. Dodge Colt and Mltsubishl ...
,
, When a car bumps Into something lit a speed as slow as 5 mph, the result too often is a severely damaged bumper plus a crumpled fender. Damage to other car parts and lights can push repair costs into the thousands of dollars. oney isn't the only problem. There's the considerable time It takes to get car repair estImates and complete the work. There's the aggravation of having to arrange for alternative transportation plus the added ago gravatlon of knowing the co Uy damage didn't have to occur in the first place. Car bumpers can be designed to live up to their nam - that is to bump and p~ teet instead of bending, denting. collapsing, and allowing extensive damage in low-
s~
4
impacts. Building a better bumper Isn't all that complicated," Insurance Institute for Highway Safety President Brian 0' eill point ou But, he notes. "when bumper styling becomes more Important than bumper function. the result too often is unnecessar and expenslve-to-repair damage in Iow-speed crashes." All new cars used to be required by federal standard to withstand front and rear crash tests at 5mph with no more than minor cosmetic bumper damage. Not anymore. Federal bumper standards were roUed back to 2.5 mph in 1 .·nce then. unlimited bumper damage ha been allowed in the required tests at the slower speed. The result is OilDSy bumper systems, lots of damage in low-speed iDl-
pacts, high repair costs, wasted time and aggravation just because of the kind of bumps that happen all the time, commonly in parking lots. In the absence of effectlve federal bumper requirements, are all bumpers equal1y flimsy? Do some perform better than others? U so, why? To answer these questions, Institute engineers recently crash tested, disassembled, examined, and compared the bumpers on 24 small 1992 model two-door cars, finding many that apparently were deslgned to look sleek or serve some function other than bumping and protecting the car from damage in . . pacts at low speeds. Based primarily on the visible damage sustained in the lnstitute's four crash tests - front-Into-flatbarrier, rear-Into-nat-barri~ front-into-angle-barrier, and rear-into-pole - ratings from "very good" to "very poor" were assigned to the bumpers on all 24 cars. The ratings begin on page 4.
a single one of the 24 small two-door cars tested this yearperformed as well as the best car a decade ago. Even the best new cars, Dodge Colt and Mltsubishl Eclipse, sustained more than $750 damage in the 5 mph tests (see table, page 3). The worst car sustained more than 3,800 damage. The Colt ustaioed DO damage in the front-into.flat-barrier test and relatively low damage totals In the other three tests. The Eclipse sustained no damage at all in (COIIt'd on page 3)
2-11HS Status Report, Vol. 27, No. J, January 25, 1992
Are AU Alike . • • Or Arelbey? Most bumpers on new cars ar~n't anything like as damage-resistant as they should be, but some do perform better than others in low-speed impacts. The problem is Jjguring Ol,lt which ones are good and which are bad - no easy task because the only Visible part of most bumper systems is the plastic cover. The diflerences among bumpers that determine effectiveness Involve primarily what's underneath the cosmetic bumper cover.
Bumper Components Typically, the basic bumper component is a reinforcement bar made of steel, aluminum, fiberglass composite, or plastic. Institute tests conducted over the years indicate that, in general, steel and aluminum ones perform best. Fiberglass bars tend to crack, even in less demanding impacts. Plastic ones generally aren't strong enough in concentrated hits to keep damage away from body parts. Besides the reinforcement bar, a bumper system may include mechanisms that compress to absorb crash energy. When they're hydraulic and there's enough room between the car body and the bumper for fuJI compressIon without allowing the bumper reinforcement bar to con-
tact body parts, such absorbers tend to perform well. Yet they're on lewer and fewer new cars. Only 2 of the 24- cars the
Institute tested this year have hydraulic energy absorbers front and rear. Others have rigid brackets while aJew cars bave collapsible brackets or other attachments. Instead, most cars have energy-absorlr ing material like polystyrene foam or plastic honeycomb, also called "eggcrate." These help prevent damage in flat impacts, which spread the force of a crash evenly over the whole face of a bumper system. But most of ilie energy-absorbing material in bumpers either isn't absorbent enough, isn't extensive enough, or it's not positioned correctly to prevent damage in concentrated impacts - for example, when a car is backed into a pole or runs into something at an angle.
StyUng VI. Damage Resistance Why don't all car bumpers do a better job of preventing damage in low-speed impacts? One reason is that styling often dictates how bumpers are made and how they're attached to cars. Damage resistance is bumped to a secondary concern. For ~x ample, some cars have rear bumpers de-
Many ofthe /992 small tWO
