Here at Building Center No.3 we are constantly searching for ways to solve problems we identify in the built environment. That premise, historically, has been the ethos of Building Centers, and this office being in Miami seeks to find problems endemic to this city. Half of our office uses public transit regularly and one of the problems we discovered while using the bus system are negative perceptions facing bus ridership. We suspect that most of the associations have socio-economic underpinnings, but as regular riders we do think taking the bus exposes oneself to specific indignities in Miami.
Here is our short list of grievances
- Miami is hot. Not fire hot. Sauna hot. A typical day in August waiting for the bus might find you in 88F, 85% humidity and no breeze. If you’re at a typical bus stop in Miami Dade County there is no canopy over the bus stop–in fact, there may not even be a bench to sit quietly to suffer. We observed people standing 15-20 steps away from the bus stop in order to stand beneath the shade of a tree–risking missing the bus or doing an embarrassing cha-cha to check if the arriving bus is the one they were waiting for.
- It rains hard–and wind driven rain is horizontal. This means that umbrellas are useless and the typical high volume bus stop does not have enough room beneath its fixed canopy to shelter 12-17 riders.
- Bus stops at night typically have poor lighting. This has the tendency to make them feel unsafe if it is not a high volume stop with lots of people waiting with you.
- When arriving at a bus stop there is always that sinking uncertainty the bus has already come and you are stuck waiting in the heat/rain for the next bus. This is an absence of real-time bus route information that might change your plans if you knew the next bus was 45 minutes away.
- Not all high volume bus stops have the route maps published. If you are a tourist or an infrequent user, it takes a number of steps on your phone to get a route map of a bus–some bus lines have alternating destinations for the same bus number: Bus #8 may have an A destination and a B destination where the route diverges depending on the time of day. With the absence of easy to understand route maps even the seasoned bus rider might find themselves on the wrong bus if the route is unfamiliar.
At BC3 we looked at the above issues as problems to be studied and solved using design solutions. We wanted any solution provided to be a mix of good architectural form and readily available technology to ensure that project is feasible in today’s market.
We looked at how we can use current technology and compelling form to address the problem of Sun, rain, public safety, and the absence of important real-time bus route information.
Our solution for the problems went through multiple designs and multiple versions of the same design–architects refer to this as an iterative design process. The design quickly evolves from the “seed” idea–in this case the idea of the fingers of a hand serving as the canopy of the bus shelter. The joints of the fingers are pivot points of adjustability in the system. These pivot points would allow the individual fingers to adjust to the position of the Sun in concert with other fingers–these positions can be predetermined based on the geo-specific and solar orientation of the future bus stop. For example if the canopy of the shelter was oriented north-south this establishes a predetermined position of the Sun in relationship to the canopy. In fact for every hour, minute and second of each day for the entire year, the Sun’s position can be tracked precisely. These positions in the sky can be programmed into software that controls the movement of each “finger.”
We envision the the Sun tracking features to be incremental adjustments that occur every 30 seconds. We began referring to the “fingers” as armatures. The armature would be designed from aluminum billet and each joint would have a low voltage servo-motor at the the pivot point. Within the structural frame we would house a small CPU that would store the solar tracking data as coordinates–similar to text files sent to a CNC machine. The fabric spanning the armatures would need the following characteristics:
- Water imperviousness
- Elasticity of 20-30% to accommodate the movement of the armatures in its many positions
We studied canopy positions that would offer the most rain protection for the greatest number of people–simply straightening the armatures to provide a flat roof would offer maximum coverage. We also looked at irrigation control system technology for simple rain sensors that would activate the rain position of the shelter so that the armatures would switch from their predetermined Sun tracking position to the flat roof position. Upon conclusion of the rain event the armatures would return to the next scheduled Sun tracking position based on the time of day. Rain sensor technology can be bought at The Home Depot for under $50.
At night, even high volume bus stops have little or no light beyond what may be emitted from advertising. Our design solution incorporates LED strip lights into the full length of each armature. At dusk the Sun tracking feature is no longer necessary, so the armatures can pitch up at a 20-30 degree angle in order to illuminate the largest area. When a bus (tracked by GPS) is within two minutes of the bus stop the LED lights in certain armatures can change from a steady white to a blinking green. Once the bus departs the light would return to white. These are helpful tools to improve public safety and provide more real-time information to the rider.
SHAPE OF THE SHELTER
In Miami many of the bus shelters are inland where they may not benefit from the coastal breezes. Also as the metropolitan area continues to densify, buildings will impede air flow at street level. Taking this into consideration we used the climate modeling software, Vasari to analyze different footprint shapes (not canopy shapes, which constantly change with the Sun) and optimize the flow of air at street level. We wanted a shape that would augment airflow in both the long direction and also laterally through the shelter. We settled on the elongated S shape because of its air movement qualities. Additionally, we designed a polycarbonate wall system inside the shelter (for personal safety to prevent someone from approaching unnoticed from behind) that is perforated with circles to allow air to pass through. These perforations could have unique graphics/patterns that could be customized to be relevant to the neighborhood or city the bus shelter is in.
We think between the optimized shape of the shelter and the perforated polycarbonate sheet we could passively maximize airflow in and around the shelter.
INFORMATION TECHNOLOGY INCORPORATED
The City of Miami bus trolleys already incorporate GPS tracking technology; the same technology would need to be rolled out for County buses. The bus shelter would have two systems to take advantage of this technology:
- LED advance warning system where the lighting color would flash green to signal the approach of a bus within a minute of its arrival.
- Each shelter would have a transparent glass touch screen that would serve as an information hub for riders seeking real-time bus route and scheduling information. This display would show the location of actual buses along the route and the arrival time based on current traffic conditions. Other major cities in the US have the technology (e.g., Boston) and the County already has the technology for the Metrorail system.
We looked at a series of challenges that we feel require further investigation or that we think we adequately addressed in our solution at his stage of development:
- Wind uplift – To address this concern we looked at the technology in six axis robotic arms. These robot arms are used in the fabrication of cars, airplanes and ships. Armatures for the shelter could be designed to be of a thickness to resist uplift. We consulted a structural engineer for the design of the structural frame anchored to the ground. The columns would be 6×6 hollow tube steel, concrete filled for increased rigidity.
- Elasticity of the fabric – We obtained fabric samples that ranged in elasticity but to achieve 20-30% and be impervious is a major challenge. We do not think the current technology available is ready for this application. More research is required.
- Cost – We think the three most expensive items would be the perforated polycarbonate barrier, the glass touch screen and the elastic fabric. Our rough estimate for the cost to produce a prototype would be 50-75k. With mass productions of the components the cost could be steadily driven downwards with large quantities of repetitive parts. However, we think an investment in high volume shelters (with the most ridership) would be good for tourism; boost morale of bus riders and increase ridership.
- Lateral strength of perforated polycarbonate – We think that by using polycarbonate sheets ½” – 1” thick, and laminated would dramatically reduce the cost, increase the strength, and decrease the weight.
- Energy consumption – We are currently studying both the embodied energy and the operational energy of the system. By using low voltage LED lights and the low voltage servo motors could dramatically limit the operational energy. Regarding the embodied energy, aluminum billet is particularly energy intensive, as well as, polycarbonate. Both materials however significantly reduce the dead load of the system.
- Resistance to vandalism – We are most concerned about the risk of vandalism in the form of puncturing the elastic fabric. Elasticity and puncture resistance are two qualities that are in opposition. Our solution is to make the canopy tall enough so that the lowest exposed edge in the Sun tracking position is tall enough to be inaccessible to anyone without a ladder. Another problem is that both sides of the fabric would also be vulnerable to graffiti. A solution to this problem needs further study.
The project reflects our office’s interest in using good design and critical thinking to identify and solve local problems creatively. We hope that these exploratory projects demonstrate our potential as an urban office solving uniquely urban problems.