A driver's loss is a biker's gain. The city transportation department says Sunday it will convert one lane of traffic along Ninth Avenue into a bicycle path.It's all part of an experimental project. The bike lanes will be installed within the next month on Ninth Avenue between west 16th and west 23rd Streets in Chelsea.Transportation officials hope the lane will cut down on accidents involving bicyclists.The design, which has been tried in Europe, will be installed within the next month on Ninth Avenue, Sadik-Khan said."It represents the kinds of innovative ideas that we can explore to make the streets more livable," she said.The project will condense cars from four lanes to three, but Sadik-Khan said traffic in the area was light enough that the change wouldn't be a problem.The city announced a $1 million bike safety ad campaign Tuesday, aiming to get drivers and cyclists to look out for each other. Sadik-Khan has said 300 cyclists were seriously injured last year, 94 percent of them due to inattention or failure to follow traffic signs.The city also is promoting bicycle riding through helmet giveaways and other means, and one cycling advocate said he thought the protected bike lane would prove a powerful incentive.Noah S. Budnick, the deputy director of Transportation Alternatives, said many would-be city cyclists "say the traffic is too scary.""If you provide protected space for riding bikes, New Yorkers are going to use it in droves," he said.