Dr. Reid Ewing, of the University of Utah’s Metropolitan Research Center, is among the nation’s leading researchers on the ability of the “7-D’s” to reduce Vehicle Miles Traveled (VMT). Dr. Ewing is an occasional consultant for Metro Analytics, and can advise communities on actions they can take to reduce VMT by means of the 7-D’s.
Here are the key attributes of 7-D Boulevards and Activity Centers:
- Density – as a center’s density increases, VMT per capita decreases. When there’s a lot close together, you’re more likely to walk, bike, or ride transit. And for those who still drive, it will be a shorter drive.
- Diversity – If homes are in suburbs, and jobs and necessary items are far away, the result is huge driving. Consider form-based codes and other strategies to reduce restrictions on specific kinds of uses, and focus instead on how well it all fits together. Mixed-uses help people get closer to things they need.
- Design – If the local street system has more connections, less circuitous paths, and fewer cul-de-sacs, it will be easier for more people to walk, bike, reach transit, and take short drives. Complete Street design also increases walking, biking, and catalyzes mixed-uses consistent with the other D’s.
- Destinations – Part of what helps define a “Place” is popular destinations that attract people from all over, such as theaters, sports arenas, etc. Transit is more likely to focus on serving centers with popular destinations, and hence more able to reduce VMT.
- Distance from Transit – It does little good to install nice transit stations, and then allow a used car lot or a gas station as the first use next to that station. People use transit if transit is close, so communities are wise to adopt minimum zoning standards within a quarter mile of a rail or BRT station (such as “at least 40 units per acre, or at least four-story buildings”). It is also good to relax or eliminate parking requirements. Developers know they must provide parking, so why risk making them build too much?
- Demographics – Many people want to live in walkable, mixed-use areas where they won’t have to drive as much. More seniors need to, and many not yet raising families want to. But if the only quality places available are single family homes, they’ll end up in those even if they’d prefer something else. If we design with changing demographics in mind, our parents and children can stay close by. They need not contribute to congestion, and the elderly can avoid “white-knuckle” driving.
- Demand Management – When vehicle demand is too high, we have three options: 1) Increase supply to match demand (usually widening roadways – which may not last long); 2) Reduce demand to match supply (make it easier and desirable for some people to choose something else); or 3) just way until it gets better – because people and jobs move out! Focus on Option 2: like helping transit get out of congestion or installing paid-parking in specific locations. Also see FreewayOptimization.org for Metro’s new Managed Motorways + Congestion Credits idea to help freeways flow without more expansion!
Here is a shorter version of the 7-D’s:
- Density of Activities: When there’s a lot that is close by, you’re more likely to walk or bike.
- Diversity of Uses: Mixed-uses help people get closer to the things they need.
- Design Connectivity & Quality: Tight grids make it easier to walk, bike, get to transit, or take shorter drives on alternative paths. Streetscape and uniform trees also boost land value, which in turn boosts density.
- Destinations: Transit targets popular destinations, so create popular destinations!
- Distance from Transit: Adopt minimum floor area ratios near stations. Replace parking minimums w/New Mobility contributions (credits for carsharing, MaaS, etc).
- Demographics: Design with changing needs in mind. Many from the youngest generations don’t want to drive, and increasing numbers of seniors shouldn’t!
- Demand Management: Create alternatives; incentives to use alternatives; disincentives for single-occupant driving: free or reduced fare transit; remove parking minimums to hasten the day when parking can be priced, etc.