Existing Conditions
The street relies entirely on the gray stormwater system, and there are few if any trees, resulting in uncomfortably hot and cold conditions. The roadbed is designed primarily to serve heavy vehicle traffic, with little or no accommodation for people biking, walking, or taking transit. Few people use the street voluntarily.
Minimal pedestrian facilities are provided, and are often blocked by trucks. Key bus routes serve the street and arriving workers, but stops have low ridership and no shelters. Riders face inhospitable waiting and crossing conditions.
Stormwater runoff entering the gray infrastructure system has large amounts of sediment, debris, and pollutants from the roadway that are either treated off-site or directed to waterways during overflow events.
Recommendations
The street has been converted from two lanes in each direction to one, with a left turn pocket where needed. Seize opportunities to align provision of safer bicycling and walking conditions with improved stormwater infrastructure.
Use green expressions, including bioretention facilities and street trees, to improve the experience of walking, bicycling, and riding transit. Integrate green infrastructure into transit stops and the planting zone to help capture and dissipate water and air pollution from the street.
Shorten crossing distances and tighten curb radii to improve pedestrian safety. Where large vehicles are expected to make turns, mountable corner aprons or concrete “pillows” can allow large vehicles to make turns while discouraging car drivers from making high-speed turns.
Adding bikeways can reveal new space within the cross-section to incorporate green infrastructure, such as bioretention cells in the bikeway buffer zone (if adequate width is available, typically at least 5 feet). Bikeways are also appropriate for permeable paving treatments since people biking incur less wear-and-tear on the surface than vehicles do. Utilize pervious concrete or porous asphalt to ensure the surface is compatible and comfortable for bicyclists.
If bikeways are configured against the curb, design with sufficient width to keep bicycles from operating in the curb or gutter. The preferred minimum width for one-way curbside bikeways is 6 feet to provide comfortable riding.
Industrial streets with high truck traffic generate large sediment and debris loads depositing into bioretention facilities, requiring large pre-settling zones at inflow points.
Test existing soils for pollutants early in the project design phase, as certain areas may have contaminants that may need to be remediated before infiltrating stormwater facilities are installed or pollutants may be transferred through the air onto the roadway from adjacent use. As industrial sites redevelop, opportunities emerge to capture and mitigate certain pollutants.
| Potential GSI Features |
| Median |
| Bioretention Swale |
 |
| Curb Extension |
| Bioretention Planter |
 |
| Planting Zone |
| Tree Well or Trench |
|
| Bioretention Planter |
|
| Parking or Bike Lane |
| Permeable Pavement |
|
The soil media in bioretention facilities in industrial areas may be multi-layered or a different mix than that used on residential yield streets, depending upon the pollutants that are intended to be treated (both from the air and street runoff).
Bioretention facilities may need to be lined to prevent existing contaminants in the soil from becoming mobile and infiltrating further into the ground.
Target installation of high-volume bioretention facilities to store and treat larger amounts of runoff.
Assess the street network for opportunities to convey water to remote sites where more water quality treatment can be implemented in large swales.
Parking lanes and bikeways can often accommodate permeable surface. Limit the amount of stormwater run-on from the travel lanes onto permeable pavement parking lanes and bikeways, since higher sediment and pollutant loads from industrial travel lanes will incur more frequent maintenance requirements.