Raidillon is the more dangerous of the two corners. The threat profile is different from Eau Rouge's:
Eau Rouge punishes loss of grip with a sideways crash into the inside or outside of the kink at the base of the valley, with the car still on the slope.
Raidillon punishes loss of grip with a blind crest and a long, fast left-hand collection zone — meaning a car off the road at Raidillon can travel a long way before stopping, often into the path of following cars.
The corner is taken near flat-out in modern F1 (with a brief throttle modulation in some conditions), at approximately 290 km/h on entry rising to 305 km/h at the crest. The vertical load reverses from heavy compression at Eau Rouge to near-zero load over the crest of Raidillon, where the car briefly "floats" — a sensation drivers describe as the most unusual on the F1 calendar.
On 31 August 2019, during the Formula 2 feature race at Spa, Anthoine Hubert lost control of his BWT Arden at the exit of Raidillon. His car struck the barrier on the right-hand side of the crest and was deflected back across the racing line — directly into the path of Juan Manuel Correa's Sauber Junior, which struck Hubert's car at almost full speed. The impact disintegrated both cars. Hubert was killed instantly; Correa suffered severe leg injuries that ended his single-seater career.
The accident was the proximate cause of the most substantial post-1994 reconfiguration of any part of Spa-Francorchamps. The Raidillon run-off was substantially enlarged in 2022, with new gravel traps installed on the climb, barrier alignment revised on the outside, and additional tarmac run-off behind the crest. Drivers reported that the corner had "lost some of its character," though it remains flat-out in dry conditions.
1985 — Stefan Bellof's fatal World Sportscar accident was on Eau Rouge proper, not Raidillon — but the chain of corners is collectively where Spa's safety record has accumulated.
1993 — Alessandro Zanardi crashed at Raidillon in Friday practice; he was unhurt but the crash was severe enough to prompt the first round of post-Eau-Rouge run-off improvements.
1998 — The 13-car first-lap pileup of the rain-affected Belgian GP initiated at Raidillon when David Coulthard lost the rear of his McLaren on the climb.
2018 — Sebastian Vettel's Ferrari briefly went airborne over the crest in a wet first-lap incident; he recovered without significant damage but the moment was widely circulated.
Raidillon is rendered alongside Eau Rouge in every Spa sim. The compression-then-zero-load transition is a known sim-tyre stress test — sim physics that don't model vertical load transfer accurately produce a Raidillon that feels too easy. Assetto Corsa Kunos models it well; AMS2's Spa_2022 includes the post-2022 run-off; ACC's spa is the pre-2022 layout; iRacing's spa/gp updated to the post-2022 configuration in 2023.