By Mark J. Probst, Houston, Texas 1-281-589-5881, probst@pbworld.com

In 2001, North Carolina’s Charlotte Area Transit System (CATS) selected PB in association with Morris Berg Architects as the prime consultant to design a new facility that would serve as its second bus operating division. CATS had been operating its fleet of more than 300 buses from the 20-year old Davidson Street facility, which was designed to accommodate 200 buses. The CATS bus fleet is projected to grow to more than 400 by 2012.

Our scope of services included space programming, site selection, master planning, and detailed design. The projected presented us with unique issues at each step of the way.

Space Programming/Master Planning

CATS’ initial concept was that the new facility would be a “satellite” facility used for light maintenance and the existing Davidson Street facility would continue to be used as the central facility. The Davidson Street facility had several significant restrictions, however:

• The site was bisected in two directions by city streets. Buses had to cross Davidson Street to get to maintenance and drivers had to cross the street to get from employee parking to the operations facility and bus parking.
• The existing administration/operations building could not be expanded easily and did not meet current code or the Americans with Disabilities Act requirements.
• The existing maintenance building could not be expanded easily and had a restricted vehicle circulation area outside of the repair bays.
• Buses were parked eight to ten deep and circulation on the site was very tight.
• Securing the site and facilities was difficult.

We also had other issues to consider, including:

• The host of operational issues that arise when a transit agency goes from operating out of a single facility to operating from multiple facilities
• Providing adequate on-site employee parking, bus parking, and safe, efficient traffic circulation
• Assuring that all operating facilities for both bus and rail had similar amenities and characteristics.

Objective Evaluation. These factors indicated an objective evaluation was required to determine what functions should be located at each facility. We used the following five-step process:

1. Identify overall system requirements
2. Evaluate existing facility capacity
3. Develop and evaluate alternative system-wide facility master plans
4. Determine the fleet size and mix to be accommodated at each facility
5. Finalize the space requirements for each facility.

Centralized and Satellite Functions. Our first step was to identify the functional and space requirements to support the projected bus fleet of 400. We met with various user groups and discussed operating and maintenance philosophies, ideal and maximum fleet size at each facility, functions that should be accommodated, and how CATS would provide services from multiple facilities. We determined that certain functions would be centralized at one facility and would support the other bus facilities in the system. Centralized functions included administration, component rebuild, heavy maintenance, major body repair and painting, electronics and fare box repair, and the parts warehouse, while satellite functions included drivers’ facilities, light maintenance, fueling and washing, and bus parking.

Capacity and Space Requirements. Results from the second step, evaluating the existing facility capacity, indicated the original design capacity of 200 buses was the maximum that could be operated efficiently from the Davidson Street site. Our evaluation took into consideration the maintenance, fuel and wash, employee parking, bus parking, and driver facilities required.

When the space requirements for drivers’ facilities to support a 200-bus fleet were compared to the existing administration/operations building, we found that almost all the space would be needed for operations and that administrative functions would have to be relocated. This led to the realization that the existing facility, rather than the new facility, was better suited for the satellite operations. The new facility would become the primary bus facility with centralized functions and would be the operating base for up to 250 vehicles.

Site Selection and Detailed Design: Making Concept a Reality

The space programming indicated that a site with at least 24 acres would be required for the second facility. For operational reasons, the ideal site would be close to the downtown transit center. Of the 18 potential sites identified, two were selected for detailed evaluation. Both were within 3.2 km (2 miles) of the downtown area, and one was a site that had been selected already for a new light rail maintenance and operations facility. We developed alternative layouts and construction cost estimates for both sites.

The light rail facility site was ultimately selected because:

• Land acquisition was simplified.
• There was a possibility that bus and light rail maintenance could share some facilities.
• The site and bus facilities could be developed within the project schedule requirements.
• The total cost for both bus and light rail facilities would be minimized.

Figure 1: Aerial sketch at South Tryon Syteet site(top):overall site plan (bottom).

Figure 2: This perspective of the front elevation along Soth Tryon street shows the clean image that is presented to the public.

Site Challenges and Solutions. Our challenges were how to contend with a severe grade change and how to fit everything on a small site. The site had a 9.6-m (32-foot) elevation change, dropping from the east along the rail line to the west along South Tryon Street. In addition, the site was only 24 acres and the bus facility alone required 24 acres assuming all functions were on one level. The conceptual layout for the light rail facility and yard took nearly the entire site.

As the solution, our team developed a concept that located the new light rail maintenance facility on the eastern third of the site parallel to the main rail line. This portion of the site is relatively flat, a characteristic that is critical for a rail facility and yard. The new bus facility is located on the western two thirds of the site with primary access directly from South Tryon, which runs along the west edge of the site (Figure 1).

We identified those functions that could be accommodated on upper or multiple levels and viewed the grade change as an opportunity rather than a problem! With the two largest area requirements being for bus parking and employee parking, our solutions were as follows:

• Locate bus parking on level grade.
• Accommodate employee parking in a 4-level, 400-car parking garage.
• Construct an 18-foot-high retaining wall across the site in a north/south direction to separate the bus parking area from the rail yard. This wall would improve safety and security for bus and rail operations and help to offset the 32-foot elevation change across the site.
• Provide a sloped bus parking and bus circulation drives, which addressed the remaining elevation change and improved drainage in these areas.

Shared Paint Facilities. The body repair and paint functions were combined in a separate facility with the finished floor at the same level as the rail yard. One of the two paint booths was configured in a drive-through arrangement and sized to accommodate a light rail car or an articulated bus. By making the paint booth a down-draft type facility, two standard transit buses can also be put end-to-end in the large booth and painted simultaneously if necessary. This approach of sharing the paint facilities for bus and rail will increase the use of the facilities and eliminate the need for duplicating specialized facilities.

Other Considerations

Security. The terrorist attacks in the U.S. on September 11, 2001 focused design attention on security as never before. The site layout with buildings along the perimeter and bus parking in the center of the site improves security. The entire site is fenced or essentially secured with the high retaining wall.

Closed circuit television and card access control were integrated into the facility from the beginning of design. A city police officer who was assigned to the design team participated in most design meetings.

Public Art. Public art was an integral part of the project. While the formal CATS’ Art Program was in its infancy at the beginning of the project, several key elements were integrated into the design including exterior brick patterns, special landscaping, and pedestrian walkways (Figure 2). An artist-designed clock will also be featured at the entrance to the site.

Conclusion

This project illustrated the importance of being objective, flexible, and open-minded during the design process. What seemed like the obvious approach initially-using the second facility as a satellite facility-did not turn out to be the best approach.