British cyclist Lizzie Armitstead has abandoned plans to ride in the omnium at London 2012 in order to concentrate on the 140km road race.
The 22-year-old - a world champion on the track and national champion on the road - had intended to compete in both.
"I don't think it's possible," she said. "It's a difficult decision."
Laura Trott or Dani King are likely to take Armitstead's omnium place - a six-discipline event making its Olympic debut in London.
The lure of winning road race gold at the finishing line on The Mall proved decisive for Armitstead.
"It's difficult to look at the velodrome and see the atmosphere that I'll be missing out on, but the whole of London will be atmospheric," said Armitstead.
"A decision is made, just because of the fact I didn't want to miss out on the road race.
"The Mall is quite iconic as well and to race down there and cross the line in a setting like that would also be very special."
The Yorkshire-born rider will now aim to be leader on the road of a British team that also includes Nicole Cooke, the 2008 Olympic champion.
Armitstead looked well placed for a medal when she was caught up in a crash late on in the finale of September's World Championships in Copenhagen. She recovered to finish seventh, while Cooke finished fourth.