sustainability | National Institute for Transportation and Communities

Taming Stormwater with Green Streets

The video begins at 12:44.

Abstract: Average Portland rainfall is nearly 37 inches a year. This rainfall usually runs off streets and other impervious surfaces such as roofs and into the sewer system, but this can cause two major problems. First, disposing of runoff in a storm sewer that drains to a river or stream sends dirt, metals, oil, pesticides, and other pollutants right into the water. Second, in neighborhoods with combined sewers, (that is, sewage systems that combine household sewage with the runoff waters from rain), after a heavy rainfall, the high volume of sewage sent to be treated can overwhelm the treatment center and lead to raw sewage discharges into the Willamette River. About 27% of the city is covered by buildings, streets, sidewalks, and other hard, or impervious, surfaces. Paved streets cover about 19% of Portland’s land area, but those streets account for nearly half of Portland’s impervious surfaces. Paved streets contribute 66% of the total annual stormwater runoff and 77% of the pollutants in the runoff. To address this problem, the City of Portland has begun investing in ways to treat stormwater runoff before it enters the sewer system. The city has built and is developing a number of “green street” projects that mimic what happens to rain when it falls on undeveloped areas. A green street uses landscaped curb extensions, lowered infiltration planters and basins, swales, trees,...

Webinar: Improving Recreational Trail Accessibility with a Volcanic Ash Treatment

PRESENTATION ARCHIVE

OVERVIEW

Recreational trails serve as valuable transportation corridors and support the health of users. Wheelchair accessibility of recreational trails depends on a variety of conditions, including slope, cross-slope, and surface characteristics. This project focused on improving the firmness and stability of a 0.2-mile section of trail that was otherwise accessible. The existing trail surface consisted of loose ¼” off-specification aggregate on native soil. A volcanic ash-Portland cement binder, studied in prior research, was batched, distributed, mixed, wetted, and compacted on site to improve the firmness and stability of the surface resulting in a smoother surface with less rolling resistance. The webinar will present details of the trail conditions, materials, batching, placement, and surface characteristics before and after treatment.

KEY LEARNING OUTCOMES

Attendees will be able to:

Describe and differentiate pozzolanic and cementitious...

Making Transit Sustainable

The video begins at 4:44.

If You're Not Part of the Solution, You're Part of the Problem: The Planner's Role in Meeting the Transportation Needs of An Aging Society.

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Webinar: Is Accessibility Planning Feasible in U.S. Shrinking Cities?

For fifteen years, scholars have claimed that accessibility-based transportation planning is at the brink of becoming a new paradigm. In contrast with traditional mobility-based planning methods, which focus on the cost of transportation per mile, accessibility-based planning methods place more importance on people's ability to reach various destinations and their access to transit systems. Its use may trail behind traditional planning methods nationally, due to vague definitions, momentum of traditional performance measures, and other factors. However, this webinar argues that accessibility-based planning is demonstrably necessary in shrinking cities across the U.S., and especially among minority populations in those cities.

As shrinking cities’ need for accessibility-based planning is distinct, the challenges to accomplishing it are also distinct and rather severe. Again, this is especially true when planning for minority populations, for whom there is often a level of mistrust in the policy process itself which must be overcome. After presenting evidence of both the especial need for and the challenges inherent in accessibility-based planning in shrinking cities (and especially among minority populations), this presentation proposes potential strategies for implementation and for applying this method in those scenarios in which it is most needed.

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