Acceleration Performance Trends and the Evolving Relationship Between Power, Weight, and Acceleration in U.S. Light-Duty Vehicles: A Linear Regression Analysis.

摘要

The acceleration performance of light-duty vehicles has implications for the energy usageof those vehicles, their attractiveness to consumers, and how they are driven. Despite thisimportance, many investigators rely on correlations from the 1970s for estimatingperformance. This paper presents a set of linear regression models for estimatingacceleration times from 0-48, 0-97, and 72-105 km/h (0-30, 0-60, and 45-65 mph), basedon engine power, vehicle weight, body style, and basic powertrain characteristics of morethan 1000 vehicles tested by Consumer Reports magazine between 1975 and 2010.Importantly, the paper includes estimates of fixed effects for each year, capturingtechnological improvements not directly observed in the data set and making the modelsappropriate for estimating performance of vehicles from many different model years.Results indicate that contemporary vehicles are better able to transform engine power intoacceleration performance than were vehicles in the past, yielding acceleration times 20-30% faster than comparable vehicles in the 1970s. Most of this improvement appears tohave occurred before 1990, and the estimated effect is larger for 0-48 km/h accelerationthan for higher-speed acceleration. One of the reported models was applied to historicsales and specification data for United States vehicles, and the results indicate that newvehicles in the U.S. today average 8.8 seconds from 0-97 km/h, 0.9 seconds (10%) fasterthan previously thought. Interestingly, the trends in 0-97 km/h acceleration times areconsistent with exponential decay toward an asymptote, and today’s vehicles are withinone second of the estimated asymptotic acceleration time.