关键词：汽车；评估成本；效益
摘 要：A comprehensive benefit-cost assessment of motorcycle use is offered, along with the characteristics, behaviors, and attitudes of motorcycle riders. U.S. motorcyclists are at high risk of crashing, with rates 24 times higher than those of passenger car and light-duty truck drivers per mile traveled. However, motorcycles require only one-quarter the parking space of a car and can reduce congestion by doubling network capacity (in vehicles per hour). Most motorcycles have high fuel economy, but low seating capacities render them little or no better than most cars and some light-duty trucks (assuming average vehicle occupancies) when compared in terms of fuel consumption per rider (or vehicle occupant) mile traveled. Motorcycles emit fewer grams of many polluting emissions but more volatile organic compounds and carbon monoxide than most cars if a catalytic converter is not installed. Noise impacts are a serious issue, with an inconsistent patchwork of regulations applied across states and localities. Results of a survey of current and former U.S. motorcyclists indicate that most respondents ride motorcycles for recreational purposes and ride in groups, but about one-half also ride for more mandatory (less discretionary) purposes and about 40% also ride solo. Fewer than one-third of respondents have formal motorcycle training, and helmet use is lowest among current riders who do not own a motorcycle. Engine size appears to be rising, and respondents support policies that combat operating a vehicle under the influence (e.g., ignition interlock devices for offenders). Regression models illuminate key factors and marginal effects on motorcycle riding and ownership rates.