I have extensive experience testing, investigating, and conducting analysis work on motorcycles, and I am very familiar with antilock braking systems (ABS). An ABS does not work when the motorcycle is not upright. This occurs when the motorcycle leans slightly to the side upon making a turn or going through a curve. Several motorcycle manufacturers just released models this year that claim to have some ABS functionality when the motorcycle is leaning to the side. However, there are still manufacturers that have not yet designed an ABS sophisticated enough to function when the motorcycle is leaning.
I have previously worked on a few cases that involved ABS accidents. In these types of cases, it’s possible that the ABS did not perform as expected, however, it’s also possible that the riders started to turn while they were breaking. There could have also been a mechanical issue causing the back wheels to lock up. Interestingly enough, a back wheel lock-up doesn’t actually involve ABS (which is the front wheel), but to a rider, the back wheel locking up would appear to be an ABS failure.