Providing Multimodal Transportation Options on Austin’s Mopac Mobility Bridges – FHWA

Figure 1: Mopac Mobility Bridges. (Image courtesy of the city of Austin)
Figure 1: Mopac Mobility Bridges. (Image courtesy of the city of Austin)

Article by Janae Spence, Urban Trails Program Manager, City of Austin, TX & Annick Beaudet, Assistant Director, Austin Transportation Department

Only two miles separate Southwest Austin neighborhoods from landmark outdoor spaces like Zilker Park, Barton Springs Pool, and the economic engine of Downtown Austin. Yet for decades, the Texas State Highway Loop 1, known as the Mopac Expressway, a corridor over the environmentally-sensitive Barton Creek, presented a barrier to active transportation options. In 2012, a funding opportunity arose for TxDOT Congestion Management funds through Capital Metropolitan Planning Organization (CAMPO), the Metropolitan Planning Organization (MPO) for Central Texas counties. Through a partnership between the city of Austin, CAMPO, and the Texas Department of Transportation (TxDOT), the city of Austin Bicycle Program was able to secure funding to close the gap in connectivity.

Around 1998, TxDOT repurposed the northbound shoulder on the bridge, eliminating bicycle access. TxDOT was also interested in converting the southbound shoulder of Mopac into an auxiliary lane for Highway 360, but wanted to avoid eliminating further bicycle access. Seizing an opportunity to solve two problems at once, the city of Austin staff approached TxDOT with an idea. The staff proposed partnering on a two-fold project that would turn the southbound shoulder of Mopac into an auxiliary lane to manage automobile congestion and provide a separate bridge for bicycle and pedestrian use. This creative, multimodal solution allowed for TxDOT to relieve congestion on Mopac and created a high-quality active transportation connection for users of all ages and abilities. As the project developed, the need for a second bicycle and pedestrian bridge became apparent to address access to the entrance ramp to Mopac. As a result, the Mopac Mobility Bridges project was born, with design beginning in 2012. The Mopac Mobility Bridges provide two miles of bicycle and pedestrian infrastructure, connecting to Austin’s urban trail network.

TxDOT and the city of Austin agreed to share the costs of the project. The city applied for a $2.5 million CAMPO grant, and the Mopac Mobility Bridges project was awarded funding. The total project cost of $14.5 million was shared between the Federal Highway Administration (FHWA) Surface Transportation Program Metropolitan Mobility funding through CAMPO, TxDOT Prop 12 Metro and Urban Mobility funding, and city of Austin bicycle-specific bond funding. This project is a great example of how partnerships between Federal, State and local governments can be key to solving problems and getting impactful projects off the ground. Specifically, FHWA flexibility for multimodal funding, coupled with innovative project scoping by the State and local governments were crucial to the project’s success.

As the project site spans the Barton Springs Edwards Aquifer, Austin’s source of drinking water, finding environmentally sensitive design and construction solutions was critical. During the planning process, the project team involved multiple water quality/environmental experts and stakeholder groups, namely the Save Barton Creek Association, Save our Springs (SOS), and the Sierra Club. Once construction began, the team found that the limestone bedrock was deeper underground than soil borings originally indicated, leading engineers to adjust the design of bridge pilings. Although this delayed construction of the project, staff again went above and beyond to include environmental stakeholders in the problem-solving process. By bringing these groups in early on, staff gained their trust and support, which was imperative to solving problems that arose during construction and ultimately bringing the bridges to fruition. In fact, without the early input and cooperation of environmental community partners, it would have been very difficult to find the best approach to meet mobility and safety objectives of the corridor and ultimately move the project forward. After three years of construction, the Mopac Mobility Bridges opened in summer 2017. The project provides a route for a daily average of over 200 bicycle and pedestrian users that previously could not cross the bridge, with the number of peak daily users at 521.

Ultimately, creative thinking, strong intergovernmental relationships, and an inclusive planning process made the project a success. The project was also strengthened by cross-agency cooperation and commitment to creative, context-sensitive solutions, participatory planning, design standards, and focused project management through completion. While initiated and motivated by bicycle and pedestrian needs, the project was most effective due to solutions that were truly multimodal and context-sensitive. Today, the Mopac Mobility Bridges provide safe, active transportation connections to jobs and entertainment, while also relieving traffic congestion and supporting accessibility for all roadway users.

Source: FHWA’s Fostering Multimodal Connectivity Newsletter – January 2018