Just weeks after Greg Van Avermaet (BMC Racing) was taken out by a moto in the Clásica San Sebastián, it happened again in Saturday’s eighth stage at the Vuelta a España.

This time it involved stage-favorite Peter Sagan (Tinkoff-Saxo). According to team staff, a neutral support motorcycle clipped Sagan’s wheel with about 6km to go, knocking him off his bike, and out of contention for the reduced-bunch sprint eventually won by Jesper Stuyven (Trek Factory Racing).

“A motor was passing the group, and he was moving left, and the motorcycle took him out,” Tinkoff-Saxo sport director Patxi Vila told EuroSport. “Peter’s feeling bad. It’s a missed opportunity of winning a stage, after the work of the whole team for him. I am sure the motorbike didn’t do it on purpose, but this shouldn’t happen.”

Sagan was enraged after the incident, kicking his bike, yelling at the motorcycle driver, and storming around the roadway in anger.

Sagan, winner of stage 3, later crossed the line furious, with cuts and scrapes to his left side, and his jersey and shorts torn open.

The 25-year-old was poised for a chance at victory after surviving two passages over the third-category Cresta del Gallo, a short but steep climb that eliminated many other sprinters, such as arch-rival John Degenkolb (Giant-Alpecin). An earlier crash took out overall favorites Dan Martin (Cannondale-Garmin) and Tejay Van Garderen (BMC Racing) in what was a very nervous day of racing in Spain.

The incident once again raises the question about where and how motorcycles and cars should move around the peloton. It seems to be a growing problem. Earlier this spring, a neutral support car also took out riders during this year’s Tour of Flanders.

“Crashes are part of cycling, but it shouldn’t happen with cars or motorcycles in the race,” said Eurosport commentator Juan Antonio Flecha, a former pro who was involved in a similar incident in the 2011 Tour de France. “This is happening too many times, and I am very upset about what happened today.”

In a similar incident earlier this month at the one-day Clásica San Sebastián in Spain’s Basque Country, BMC’s Van Avermaet was knocked off his bike by a motorcycle while making a promising move on the final climb before the finish line. Adam Yates (Orica-GreenEdge) later won the race.

“Unfortunately, it isn’t the first time such an incident happens,” Sagan said after the stage. “Even if motorbikes are forced to go through a group of riders, they should do it very carefully and not recklessly. In my opinion, motorbike drivers don’t take the safety of the riders in consideration seriously. Fortunately, my injuries aren’t very serious but can you imagine what would have happened if he had ran over me?

“If I had crashed alone or with another rider, I would have considered that to be part of the sport. However, being hit by a motorbike of the race organization shouldn’t be acceptable. The safety of the riders should be an absolute priority and all vehicle drivers involved in a race must be more attentive. I really hope this incident is the start of a series of necessary changes in the way races are organized.”

In a team press release, Tinkoff-Saxo raised the possibility of taking legal action in response to the incident.