5th/6th Street Livability & Circulation Study
Traffic Circulation
There was strong predisposition by some members on the CCAG to reduce the number of through lanes along 5th/6th Street. The project team evaluated the potential traffic-circulation impacts of reducing the number of traffic lanes from four to two along 5th/6th Street over the entire seven-mile corridor. This analysis indicated a high potential for significantly increased congestion along 5th/6th Street. The analysis also indicated a potential for significant traffic diversion from 5th/6th Street to Speedway Boulevard, Broadway Boulevard, Grant Road, and University Boulevard, increasing congestion along these alternate routes.
Downgrading a four-lane road to a two-lane road with a center turn lane offers significant safety benefits. Left-turning vehicles are taken out of the traffic stream, reducing the number of left-turn and read-end accidents. Preliminary alternatives presented to the CCAG for consideration involved a three-lane cross section east of Campbell Avenue, where there is presently a four-lane roadway configuration. Many, but not all, west-end representatives of the corridor perceived that different treatments were being considered for 6th Street west of Campbell. They pointed out the existing urban form, high pedestrian activity, and historical nature of the west end was different than the east end, but they argued that treatment for 5th/6th Street should be the same from end-to-end. The CCAG initially agreed.
Traffic speed was a concern that emerged in Phase I. Likewise it was often discussed in Phase II. The CCAG was concerned that signal progression efforts of traffic engineering are at odds with posted speed limits on 5th/6th Street, effectively encouraging motorists to speed along the street. A special session with City of Tucson traffic engineering staff was conducted so that CCAG members could tour the City of Tucson’s Operations Center. Following the session, the CCAG members decided that this study was not the appropriate venue for addressing this issue.
Preliminary right-of-way information indicates that right-of-way width is highly variable from block to block, but generally ranges between 80 and 90 feet. A significant exception to this is east of Country Club Drive, where the right-of-way is only 60 feet wide. Concerns for existing land uses, historic structures and property owners developed into a CCAG recommendation that existing curbs should be maintained, and any new facilities (e.g., bike lanes, medians, and pedestrian refuges) should be provided to the extent possible within the existing curb-to-curb distance. Deviation from this principle in Phase III is to be permitted only upon approval of neighborhoods, businesses and other affected parties. This position allows some flexibility of design to incorporate the desired new features for the corridor. The CCAG also discussed the possibility of using 10 foot or 11 foot lanes in future designs. Consideration of this will be addressed in Phase III.
