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27 The project team agreed to model a future year of 2020 as doing so would require minimal network changes and, it was hoped, would allow for the model trip tables to work within the DTA without preconditioning. The project team also agreed to limit any network changes (automobile and transit) to the Southwest Corridor study area, because all the scenarios planned for simu- lation were within the TriMet service area. Metro staff worked closely with various stakeholder groups within Metro and the FAST-TrIPs team to identify the necessary transit changes that would need to occur to the base transit network for each of the scenarios. Here is the final list of scenarios: 1. Bus rapid transit (BRT) to Tualatin, operating in an added exclusive transit right-of-way (ROW). BRT would travel primarily on Barbur Boulevard between downtown Port- land and the Tigard city line and through the Tigard Triangle to reach the downtown Tigard Transit Center. The align- ment would use Hall Boulevard, Durham Road, and Upper Boones Ferry Road between Tigard and Tualatin, terminat- ing at the Westside Express Service commuter rail station. This alternative would remove no roadway capacity. 2. BRT to Tualatin, operating in converted automobile lanes, in an exclusive transit ROW. Using the same alignment as the first alternative, this alternative would remove one lane of automobile capacity in each direction for the entire align- ment where at least two automobile lanes currently exist for the exclusive use of transit vehicles. This BRT would be center running, restricting left-turn access for automobiles to signalized intersections. 3. BRT to Tualatin, operating in converted automobile lanes, in business access and transit lanes. This alternative would convert automobile lanes in the same road segments as the second alternative, but it would include a curbside-running BRT that would allow autos in the transit lane with restric- tions. Automobiles would be allowed in the lane only to make right turns to exit the street to driveways or inter- secting streets or to enter the street in order to merge into the general traffic lane. 4. I-5 active traffic management. This alternative would include installation of sensors and variable message signs, and use of other techniques such as variable speed limits, to reduce congestion and improve safety on I-5 for the length of the corridor. Table 4.1 and Table 4.2 list additional proposed projects on I-5 and OR-99W, respectively, that were removed from con- sideration as part of the Southwest Corridor Plan. The project team believes that these scenarios will provide a good mix of changes to both automobile and transit travel time reliability; they also provided our workshop participants with interesting data on the various trade-offs between automobile and transit projects. Once the BRT system is coded for one sce- nario, it should not require too much additional work to make it work in the other scenarios. Not all projects listed in Tables 4.1 and 4.2 were modeled. However, the project team did model simplified intelligent transportation systemsâstrategy scenarios by using variable message signs (VMSs) on Barbur and I-5. Details of such models are presented in Chapter 7. C h a p t e r 4 Process for Prioritizing Operational and Capital Improvements
28 Table 4.1. Scenario Details for I-5 Projects Location Project Details Cost I-5 Active traffic management Install sensors and variable message signs and use other techniques, such as variable speeds, to reduce congestion and improve safety. $7,000,000 I-5 Southbound climbing lane: Hood Avenue to Terwilliger Boulevard Phase 1: Hood Avenue entranceâsouth of Corbett, $25M; Phase 2: south of Corbett-Brier Place, $18M; Phase 3: Brier Place-Terwilliger exit, $20M. $250,000,000 I-5 Congestion and bottleneck operational improvements This project would construct several improvements to address recurring bottlenecks on I-5 south of the central city. Two priority projects include constructing a southbound auxil- iary lane along I-5 from the SW Lower Boones Ferry Road interchange to the SW Nyberg Street interchange and reconstructing the SW Lower Boones Ferry Road off-ramp from one to two lanes. Other projects include auxiliary lanes, ramp reconfigurations, changes to striping, and intelligent transportation systems. Could be constructed in phases. $220,000,000 SW Portland I-5 diamond interchange Construct a diamond interchange at I-5 and SW 26th, remove existing Spring Garden ramps, and remove northbound Taylorâs Ferry off-ramp. $86,000,000 SW Portland I-5 partial split interchange Reconfigure the I-5 Spring Garden interchange as a partial split by creating I-5 southbound ramps connecting to Barbur Boulevard just south of SW 26th and creating northbound on- and off-ramps at Spring Garden. Would close existing southbound off-ramp at Spring Gar- den and northbound off-ramp at Taylorâs Ferry. Could be constructed in two phases. $79,900,000 Table 4.2. Scenario Details for OR-99W Projects Location Project Details Cost Highway 99W improvements (Cipole to Tualatin River) Widen 99W to six lanes from Cipole to the Tualatin River. $27,300,000 Highway 99W Transportation System Management and Operations New Transportation System Management and Operations projects on OR-99W to install variable message signs, cameras, and road weather information systems. $150,000 Highway 99W/68th Avenue Intersection improvements such as protected left-turns at 68th (final improvements to be determined on further refinement). $1,000,000 Highway 99W/I-5 southbound Intersection improvements such as dual northbound through lanes on 99W and dual lanes for I-5 to reduce confusion, congestion, and related accidents (final improve- ments to be determined on further refinement). $5,000,000 99W and Canterbury Intersection improvements such as a westbound left-turn lane (final improvements to be determined on further refinement) at 99W and Canterbury. $2,000,000 Highway 99W intersection improvements Provide increased capacity at priority intersections, including bus queue bypass lanes in some locations, improved sidewalks, priority pedestrian crossings, and an access management plan, while retaining existing four- and five-lane facility from I-5 to Durham Road. Could be constructed in phases. $94,900,000 Pacific Highway 99W (access management) Implement access management strategies and median projects in Highway 99W Plan. $6,000,000
