Robert Cervero

The relationship between transit success and density is one that should be considered when planning transportation. Transit lines need to consider cost per passenger-mile in order to ensure financial feasibility. Some scholars suggest minimum density thresholds for successful transit of different types, but these rules do not always represent accurate ridership numbers. However, higher density in cities generally makes transit more feasible.

Concerns over rising fuel prices and greenhouse-gas emissions have prompted research into the influences of built environments on travel, notably vehicle miles traveled (VMT). Accessibility to basic employment has comparatively modest effects, as do size of urbanized area, and rail-transit supplies and usage. Nevertheless, urban planning and city design should be part of any strategic effort to shrink the environmental footprint of the urban transportation sector.

"Beyond Mobility is about prioritizing the needs and aspirations of people and the creation of great places. This is as important, if not more important, than expediting movement. A stronger focus on accessibility and place creates better communities, environments, and economies. Rethinking how projects are planned and designed in cities and suburbs needs to occur at multiple geographic scales, from micro-designs (such as parklets), corridors (such as road-diets), and city-regions (such as an urban growth boundary). It can involve both software (a shift in policy) and hardware (a physical transformation). Moving beyond mobility must also be socially inclusive, a significant challenge in light of the price increases that typically result from creating higher quality urban spaces."