With ESC dramatically reducing rollover risk, the inherent advantages offered by SUVs' greater size, weight, and height emerge more clearly. Today's SUVs have the lowest driver death rate of any vehicle type." The high danger for cyclists and pedestrians of being seriously injured or even killed by SUV drivers has caused some public protests against SUVs in urban areas. In 2020, a study by the US-based IIHS found that, of a sample of 79 crashes from three urban areas in Michigan, SUVs caused more serious injuries compared to cars when impacts occurred at greater than . The IIHS noted the sample size of the study was small and that more research is needed. Environmental impact SUVs generally have poorer fuel efficiency than smaller cars, and thus contribute more to environmental degradation and global warming. SUVs emit about 700 megatonnes of carbon dioxide per year, a gas that is linked to global warming. According to the International Energy Agency, from 2010 SUVs have been the second-largest contributor to the increase in global emissions, second only to the power sector. SUVs were responsible for all of the 3.3 million barrels a day growth in oil demand from passenger cars between 2010 and 2018, whereas efficiency improvements in smaller cars saved over 2 million barrels a day, with electric cars reducing oil demand by under 100,000 barrels a day. Whereas SUVs can be electrified, or converted to run on a variety of alternative fuels, including hydrogen, their (manufacturing) emissions will always be larger than smaller electric cars. On average, SUVs consume about a quarter more energy than medium-size cars. Furthermore, the vast majority of these vehicles are not converted to use alternative fuels. Between 2010 and 2018 SUVs were the second largest contributor to the global increase in carbon emissions worldwide. Types of SUV Crossover SUV The "crossover SUV" segment (also known as "CUVs" or simply "crossovers") has become increasingly popular since around 2010. Crossovers are often based on a platform shared with a passenger car, as a result, they typically have better comfort and fuel economy, but less off-road capability (many crossovers are sold without all-wheel drive) than pickup truck-based SUVs. The difference between crossovers and other SUVs is sometimes defined as a crossover being built using a unibody platform (the type used by most passenger cars), while an SUV is built using a body-on-frame platform (the type used by off-road vehicles