Intersection of Transportation and Demographics

The issue of the elderly and transportation has been a topic of news articles around the country lately (USA Today 12/2, W. Post 12/7, Appleton Post-Crescent 12/9, San Diego Union Tribune 12/8). Most of these focus on providing volunteer or low-cost rides to old or infirm people to help them get where they need to go.

My sense is that transportation planners do not typically take future demographics into consideration very well. In particular, when planning is made for transportation infrastructure that will be in service for 40-50 years, there will always be statistics on future traffic demands on that infrastructure, usually used to help justify and plan the project. My experience with my own aging relatives is that long before they need to stop driving altogether, they find driving on expressways and freeways at high speeds very uncomfortable. All those 40-somethings who are using the Springfield interchange and Woodrow Wilson Bridge now will be 70-somethings in 30 years. Are we designing the long-term infrastructure in a way that will accommodate the demographics not as they are now, but the demographics as they will be decades in the future? I have never read anything in the planning for transportation projects like these that expressly discusses that issue. If you have, I'd be interested in hearing about it.