Rebecca Allen and Jennifer Garvey were out for an early-morning ride in Fort Collins, Colorado when they were struck by a 2004 Saab driven by a 20-year-old man suspected of drinking and driving.
Both cyclists were wearing helmets and riding in the bike lane. The Saab struck both bicycles from behind, say Fort Collins police.
Allen, age 32, was taken to a local hospital where she died of her injuries. Garvey, 36, was also taken to a hospital where she was treated for serious injuries.
Police questioned and arrested Daniel Price of Fort Collins on suspicion of driving under the influence. He was taken to the hospital for blood tests to determine his alcohol level. Police said additional charges against Price are pending as the investigation continues.