Tocome up with these findings, the IIHS analyzed police-reported crashes in sevenstates (Florida, Illinois, Kansas, Maryland, Missouri, New Mexico, and Utah)during 2001 and 2002, as well as data from the federal Fatality AnalysisReporting System.
Theresearchers analyzed the crash rates (all crashes, injury crashes, and fatalcrashes per registered vehicle year) of cars and SUVs with ESC as standardequipment versus prior versions of these vehicles when they weren't equippedwith ESC, or when ESC was available only as an option and almost universallyignored by consumers.
Thecomparison vehicles were restricted to earlier models that were physicallyidentical to the ESC-equipped vehicles in all respects except for ESC.
Asuseful as any ESC system might be, it's worth noting that they are not allidentical. ''The hardware is similar,'' Ferguson says, ''but there arevariations in the way the systems are programmed to respond once loss ofcontrol is detected.'' They all apply a brake as required, but the method andtiming of cutting back on engine power without driver input varies from modelto model.
Carcompanies that market performance are often more conservative with the way theyapply ESC, since it does require taking significant control away from thedriver, and that upsets a number of people.
It'spossible, then, that one company's system is actually more useful than anotherin a given situation, but Ferguson says the data isn't extensive enough to makethat call.
Ona like note, said Ferguson, there's no way to compare ESC effectiveness in carsversus SUVs.
''SUVstypically have high single-vehicle rollover rates, and these crashes usuallyinvolve drivers losing control of their vehicles,'' Ferguson says, ''so itwouldn't be surprising if SUVs benefited more from ESC. This will be a subjectof future study when more vehicles are equipped with ESC and data are moreplentiful."
Whilethat would certainly be an interesting study, for the consumer it seems clearthat they should pay more attention to whether their new vehicle comes ESC, andthe import of that would increase the higher the vehicle.
photo:General Motors
Theresearchers analyzed the crash rates (all crashes, injury crashes, and fatalcrashes per registered vehicle year) of cars and SUVs with ESC as standardequipment versus prior versions of these vehicles when they weren't equippedwith ESC, or when ESC was available only as an option and almost universallyignored by consumers.
Thecomparison vehicles were restricted to earlier models that were physicallyidentical to the ESC-equipped vehicles in all respects except for ESC.
Asuseful as any ESC system might be, it's worth noting that they are not allidentical. ''The hardware is similar,'' Ferguson says, ''but there arevariations in the way the systems are programmed to respond once loss ofcontrol is detected.'' They all apply a brake as required, but the method andtiming of cutting back on engine power without driver input varies from modelto model.
Carcompanies that market performance are often more conservative with the way theyapply ESC, since it does require taking significant control away from thedriver, and that upsets a number of people.
It'spossible, then, that one company's system is actually more useful than anotherin a given situation, but Ferguson says the data isn't extensive enough to makethat call.
Ona like note, said Ferguson, there's no way to compare ESC effectiveness in carsversus SUVs.
''SUVstypically have high single-vehicle rollover rates, and these crashes usuallyinvolve drivers losing control of their vehicles,'' Ferguson says, ''so itwouldn't be surprising if SUVs benefited more from ESC. This will be a subjectof future study when more vehicles are equipped with ESC and data are moreplentiful."
Whilethat would certainly be an interesting study, for the consumer it seems clearthat they should pay more attention to whether their new vehicle comes ESC, andthe import of that would increase the higher the vehicle.
photo:General Motors