Hybrid vehicles take the best of both systems efficiency of electric power at low speeds and range of i.c.e. and combine them into one motive system. Also, cars tend to emit more pollutants at idle speed than higher rpms. Reduction in Use Anything that reduces use of cars is the cheapest and easiest way to cut down energy expenditures and emissions. One of the ways to reduce energy costs and emissions in transportation is to alter the shape of cities. Brazil Importance of Density Density is a key variable.
Transportation engineers use land use variables, among others, to predict traffic volumes.
One alone is not very effective in reducing emissions and energy consumption. Smith and Raemakers argue that the linear design of Curitiba is not enough to reduce energy consumption. More mixed land use would improve the efficiency of the system. Mixed use was part of the plan, but did not occur. Inertia of the Built Environment One of the problems with providing transportation to cities is that the infrastructure is, for the most part, fixed.