This is the V-不-C potential complement pattern: 刹 (brake) + 不 + 住 (hold/stay). 住 here means 'come to a halt'. The affirmative form is 刹得住 (can stop).
usage
Used both literally (vehicles) and figuratively (laughter, anger, gossip, momentum). 刹 is also pronounced chà in Buddhist words like 古刹 (ancient temple) — different word.
