... I've come across a LOT of people who don't understand that ABS is designed NOT so that you stop faster, but rather so that you can maintain your ability to steer in a panic situation...
No doubt this is a passionate topic, but Cosmo has bullseyed an important fact.
This isn't intended as a rant nor do I intend to debate with anybody; call it just my 0. 02 if that helps. Many drivers don't have deep understanding of how the various systems on an automobile work. Also, many don't have much knowledge of physics in conjunction with how suspension and brakes work. Not faulting anybody, just observing that's how it is. They put fuel in the tank and drive. Statistics this way or that, what the ABS system mainly solves is to keep the steering tires rotating so the vehicle will respond to steering inputs during heavy braking. To a lesser degree, ABS helps keep the rear end planted, but is not infallible there as one of the replies above testifies. I personally have witnessed at least two accidents from years ago before ABS was prevalent, both on rainy nights at an intersection, both where people were pushing their luck on a yellow light, both resulted in collision because the front tires locked up and the car did not respond to the driver turning the steering wheel. (and yes I'll agree- because the driver did not have skill, presence, whatever, to let up on the brakes) (Both were relatively minor accidents- bent metal but no personal injuries)
I can't quote chapter and verse here, but my memory is that ABS is known to lengthen stopping distances, and the evolution of ABS has included the pursuit of minimizing that extra distance (compared to what an experienced performance driver can do... ).
Seems that OP may have encountered a "worst case" situation. While I'd agree in general that the OP's encounter was probably ABS related, personally I dunno if I could be 100% sure about that. I acknowledge another fact; I wasn't there, and the OP was. I sure have encountered lots of times (mostly on smooth ice) when I was standing on a brake pedal and listening to the ABS work and not slowing down nearly as fast as I thought I should be, and wishing that I had an "ABS-OFF" switch. [edit: with other vehicles in the past, not my Dodge truck, which isn't driven in winter... . ]
I'll close with a couple stories, hope they aren't too boring-
My 1990 GMC 2500 4x4 manual trans- back then had only rear ABS. Worked ok in the warm especially if slowing down on bumpy surface, did a good job at preventing the wheels from locking if the axle hopped. But... On cold winter mornings, first stop of the morning... it wasn't a hydraulic issue, it was an electric issue- the "system" would sense the brake lights come on, and the ABS would come in and absolutely lock the rear end. It would stall the engine if you weren't fast enough with the clutch. If you happened to be on slippery road at the time, that action would often also start the rear end coming around. Only happened on first application or two of the brakes, when very cold out. (I have to believe it may have been a software issue more than mechanical) I complained to the dealer, the issue was repeatable and acknowledged, several nondescript attempts to fix. Finally the dealer told me that central tech office final suggestion for "solution" was to saturate the rear (drum) brake shoes with oil. I said no thanks to that. I learned when first starting out on a cold morning, get her into 2nd gear and apply some throttle and touch the brake pedal with left foot, ride it a couple times for 100 feet or so, it was usually ok after then.
1993 S-10 blazer, had 4 wheel antilock brakes. Out on a date one night, maybe 3rd or 4th date with this particular lady. Cold winter night, we were driving slowly through old neighborhoods, she was showing me where she grew up. I happened to lightly touch the brakes while over a frozen patch, and the ABS came on lightly. In that vehicle, it sounded a lot like what can happen after a big dinner at taco bell. She abruptly stopped talking and looked at me accusingly. I told her it was the ABS brakes. With doubtful tone, she said "make it do it again... ". I had to find another icy patch and repeat the process to convince her I hadn't done anything inappropriate. I completed that successfully, and made a mental note- she ain't the one...