The City of San Diego uses Transportation design guidelines that you might be interested in. California law requires city agencies to develop regional community plans which establish development densities, which are used for long term traffic projections. This allows right of way to be established and phasing of road improvement to correspond to density increases. This works well, except new federal laws require agencies to go back and increase density to account for affordable housing. The affordable housing is high density and was not planed for, so in many cases it ruins the area making commute times terrible. The Federal standards work well where there are train/subway infrastructure that can easily increase schedules to account for the higher density. But most of California is car dependent, and low income people tend to work multiple jobs here because of the high cost of living. So it is not practical for most low wage workers to use public transportation because of the time involved. It would make more sense to build high speed trans out of the major cities to undeveloped new cities, too far away to drive. This would make
It possible for private citizens to build for proffit housing that low wage people could afford as land values would be far cheaper. This would take competitive pressure off of housing in major job centers stabilizing prices so more can afford to purchase condos/homes. In addition, the workers that had jobs that could easily access the high speed trains, would not need cars in the major cities. As you can imagine, existing citizens that would have increased commute times when high density housing is proposed are very resistant.
In conclusion. If one is planning to increase housing densities over time, it is recommended that a strong public below ground subway/ above street level moving sidewalk system be incorporated as development occurs. Paris is an example of a city where you can get anywhere quickly with little walking. Streets are used mostly for trucks and for separate disabled persons transportation.