Paved Greenways and Roadway Con- siderations Greenways are linear features by their nature, which means they must eventually extend along and across barriers such as roadways. Two - way greenways adja- cent to roadways have inherent operational challeng- es, but they can be mitigated with careful design. De- sirable paved greenway alignments that follow road- ways maximize the separation of greenway users from motorized vehicle traffic. Wide buffers also provide space for healthy trees and utilities. In addition to longitudinal buffers from the roadway edge, access management can be used to minimize the frequency and width of driveways that cross the greenway. Paved trails may also be incorporated into County parks or other sites. The primary consideration in the design of intersec- tions with roadways is to minimize the exposure of greenway users to traffic. Exposure can be minimized at intersections by visually highlighting the crossing, shortening crossing distances, using physical deflec- tions to slow traffic, or by adding signals to provide dedicated time to cross. Another design element of greenway intersection design is the physical re- striction of access by motorized vehicles. Physical barriers across greenways should be limited to locations where absolutely necessary to prevent access by motor vehicles. Strategically placed curb islands are effective and appealing methods of limit- ing access by motorized vehicles. Properly designed curb islands can limit passenger vehicles while still
maintaining access for emergency vehicles ( Figure 23 ).
As the volume and speed of roadway traffic increases, so does the desirability and safety of grade - separating greenway crossings. Underpasses are more suited to maintain the natural greenway envi- ronment, minimize steep ramps, minimize exposure to roadway noise, maximize protection from weather, and remove the issue of debris falling upon the road- way. Florida ’ s low elevation and high water table can limit the locations that are suitable for underpasses, but roadway bridges over waterways and other road- ways present conditions that can increase the feasibil- ity and inclusion of underpasses. Several intersections along the Upper Tampa Bay Trail present a best prac- tice example where the pathway splits and leads to both an underpass and a signalized crossing, provid- ing direct route options for users accessing the greenway at the roadway crossing and those just passing through. Bridge spans can be designed to be sufficiently wide and tall to incorporate safe greenway crossings and maintain the ecology of stream corri- dors ( Figure 24 ). Intuitive access alignments and an appealing environ- ment can encourage use, discouraging attempts to cross the roadway in unsafe locations. Greenways both over and under roadways can become destina- tions of their own when designed as appealing public spaces with adequate lighting and enhancements such as public art ( Figure 25 ). In addition to aesthet- ics, lighting and art can improve both the safety and security of greenway users. Well - lit and well - traveled areas can also discourage undesirable behaviors.
Figure 23. Use of median to restrict vehicle access
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HILLSBOROUGH COUNTY GREENWAYS AND TRAILS MASTER PLAN
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