Highway Improvement Alternatives
Multiple highway improvement alternatives were conceptualized and presented for consideration as part of the Alternatives Analysis. Previous studies, the 2014 US Route 422 West Shore Bypass Reconstruction Study, input from PennDOT and brainstorming sessions were used to develop design alternatives for both the Penn Street/Penn Avenue Interchange and Lancaster Avenue Interchanges. As a result of this screening process, preferred alternatives for the Penn Street/Penn Avenue Interchange and Lancaster Avenue Interchanges were developed by the project team and are presented below. Input regarding these alternatives will be gathered through public presentations, including this website.
A work zone analysis was conducted to determine expected delays for lane reductions during construction. The results determined that any reduction in available lanes would result in excessive delays. Therefore, the objective is to maintain two travel lanes on US 422 in each direction during construction for both operations and incident management.
Design year traffic analyses warrant an ultimate six lane typical section from the western end of the project to the Lancaster Avenue Interchange. From Lancaster Avenue to the eastern end of the project a four lane typical section is adequate to maintain acceptable levels of service for the design life of the project, however the need to maintain two lanes of traffic in each direction during construction requires the construction of a wider overall roadway footprint, most notably at the three Schuylkill River crossing bridges. These major structures currently have twin-girder configurations, which do not accommodate phased construction. Therefore, the mainline structures from Lancaster Avenue through the eastern end of the project would be constructed to accommodate a six lane typical section, in order to maintain two lanes of traffic in each direction during construction, and the alignment of US 422 through this section would be adjusted to allow the bridges to be reconstructed in this fashion. In addition to the mainline structures requiring a wider footprint, the median through the S-curve from Lancaster Avenue to Brentwood Drive would be widened and the embankment on the inside of the curves would be cut back in order to provide proper sight distance.
US 422 Mainline Alternative
The US 422 mainline would generally follow the existing alignment and the proposed typical section would consist of three 12’ lanes in each direction. The mainline would also have a typical median section of 22 feet including two 10’ shoulders and a 2’ median barrier. A wider median would be provided in the S-curve between Lancaster Avenue and Brentwood Drive to meet current horizontal sight distance criteria. All horizontal and vertical alignments would meet current design criteria. A design exception would be required at the Buttonwood Street Bridge because the shoulder widths would be reduced to accommodate three 12’ lanes through each existing arch barrel. The Buttonwood Street Bridge is on the National Register of Historic Places; therefore, replacement of the structure to provide the required shoulder widths is not anticipated. See proposed Buttonwood Plan Detail.
Along with the US 422 mainline, the existing N. Wyomissing Boulevard and I-176 Interchanges would be reconstructed. The configuration of both interchanges would remain, however they would be updated to accommodate a six lane mainline section and to meet current design criteria for ramp acceleration and deceleration lengths.
At the N. Wyomissing Boulevard Interchange, the third eastbound mainline lane would be introduced at the PA Route 12/Warren Street Bypass on-ramp and continue through the interchange area. In the westbound direction the third lane will continue through the interchange area and drop at the US 222 S/US 422 W exit.
The N. Wyomissing Boulevard Interchange bridge would be replaced to provide adequate horizontal clearance for the widened mainline as well as the required 16’-6” vertical clearance. The new bridge would also be widened to accommodate WB-67 (interstate semi-trailer) turning movements at the ramps. The widening would result in a bridge capable of carrying four lanes of traffic plus shoulders should N. Wyomissing Boulevard ever be extended across the Schuylkill River to provide another connection between Wyomissing with the City of Reading. The ramps would be lengthened to provide acceleration and deceleration lengths required under current design criteria. The mainline widening would also require the replacement of the overhead Norfolk Southern Railroad Bridge to the west of the interchange. See proposed N. Wyomissing Boulevard Interchange.
The I-176 Interchange bridge would also be replaced to provide adequate horizontal clearance for the widened mainline as well as the required 16’-6” vertical clearance. The ramps would be widened and lengthened to provide acceleration and deceleration lengths required under current design criteria. The geometry of the ramps in the trumpet interchange would be updated to meet the required design criteria and allow for construction while maintaining traffic on the existing ramps. The new acceleration lanes to US 422 eastbound and westbound would extend onto the adjacent structures over the Schuylkill River.
The third westbound mainline lane would be introduced at the I-176 on-ramp and continue through the project area. In the eastbound direction the third lane would drop at the I-176 interchange, with the two remaining mainline lanes continuing through the interchange area to the eastern end of the project.
The mainline alignment would be shifted to the north in this area to accommodate construction of the two Schuylkill River bridges, which cannot facilitate part-width construction. In addition, the shift to the north would eliminate impacts to the Schuylkill River Greenways Association (SRGA) trail located between I-176 and the power plant waste area in the southwest quadrant of the interchange. See proposed I-176 Interchange.
Penn Street/Penn Avenue Interchange
The Penn Street/Penn Avnue Interchange is constrained by the Schuylkill River to the east and the Norfolk Southern Railroad to the west. The design for Penn Street/Penn Avenue Interchange would tie into the typical section of the proposed Penn Street/Penn Avenue Interchange Bridge Rehabilitation project over the Schuylkill River, which is scheduled to begin construction in 2017. This includes four 11’ lanes, 5’ shoulders, and 6’ median. The design to the west would tie-in before reaching the Norfolk Southern Railroad bridge over Penn Street/Penn Avenue Interchange, which has a vertical clearance of 13’-8”. If the bridge is impacted as a result of the interchange design, not only would the bridge replacement be costly, but obtaining the required vertical clearance would create vertical geometry challenges along Penn Street/Penn Avenue Interchange.
Design year 2046 traffic volumes were used in the capacity analysis of the Penn Street/Penn Avenue Interchange alternatives. No new traffic assignments or diversions to or from other interchanges are expected with any of the configurations examined. Due to the unconventional geometric configurations that were evaluated at this interchange, a microsimulation analysis tool, VISSIM, was used in addition to traditional Synchro and Highway Capacity Software (HCS) analysis. This aided in evaluating how all of the different elements of the interchange design interact and affect adjacent segments, and in validating the results of the Synchro and HCS analyses.
Diverging Diamond Interchange (DDI)
A Diverging Diamond Interchange (DDI) is a type of diamond interchange in which two directions of traffic on the non-freeway road cross to the opposite side on both sides of the bridge at the freeway (See proposed Penn Street/Penn Avenue interchange here / Watch Video).
The DDI allows for two-phase operation at all signalized intersections within the interchange. This design improves the efficiency of an interchange, as the lost time for various phases in the signal cycle can be reserved for the green time. Pedestrians use signalized pedestrian crossings and are directed to a center pedestrian island in the middle of the roadway between the two crossover intersections.
The US 422 off-ramp right turns would typically be stop controlled. This DDI configuration proposes the eastbound US 422 off-ramp right turn onto Penn Street/Penn Avenue Interchange westbound to be stop controlled, while the westbound US 422 off-ramp right turn onto Penn Street/Penn Avenue Interchange eastbound be signalized. The two right turn movements from Penn Street/Penn Avenue Interchange onto US 422 would continue to be uncontrolled movements as they are currently. Pedestrian accommodations at the uncontrolled locations would be incorporated into the design. The DDI design would also eliminate the existing sight distance triangle issue for pedestrians.
The proposed configuration would also impact the first span of the Penn Street/Penn Avenue Interchange bridge over the Schuylkill River.
Lancaster Avenue Interchange
The Lancaster Avenue interchange is constrained by the Bingaman Street Bridge, Thun Trail, Gerber-Bitting Cemetery, Schlegel Park, and the Reading Fire Department Southwest Station at the PA 10/Lancaster Avenue Intersection. Furthermore, any design at Lancaster Avenue must account for the intersection of PA Route 10 with Lancaster Avenue to the immediate south of the interchange. The existing bridge carrying US 422 westbound over Lancaster Avenue has a vertical clearance of 14’-6”, below the current minimum requirement of 16’-6”. As profile changes along Lancaster Avenue would result in difficulties at the tie-ins north and south of the interchange, the profile of US 422 would be raised in this area to achieve the required clearance.
The design for Lancaster Avenue would require reconstruction or replacement of the Bingaman Street Bridge. This structure currently carries four 11’ lanes with no shoulders or median, and 6’ wide sidewalks along both sides of the bridge.
Design year 2046 volumes were used in the analysis of the Lancaster Avenue interchanges for all recommended alternatives. No new traffic assignments or diversions to or from other interchanges are expected with any of the configurations examined. Due to the unconventional geometric configurations that were evaluated at this interchange, a microsimulation analysis tool, VISSIM, was used in addition to traditional Synchro and Highway Capacity Software (HCS) analysis. This aided in evaluating how all of the different elements of the interchange design interact and affect adjacent segments, and in validating the results of the Synchro and HCS analyses.
Offset Interchange with Westbound Underpass
A modified diamond layout was investigated for the Lancaster Avenue Interchange based on the preliminary Option 4 from the 2014 US Route 422 West Shore Bypass Reconstruction Study. The modified diamond layout was further modified to provide a single intersection along Lancaster Avenue (See proposed Lancaster Avenue interchange here / Watch Video).
This alternative is closely related to the original study option but relocates the US 422 westbound off-ramp from directly intersecting Lancaster Avenue to a flyover ramp joining the new signalized access point on PA Route 10 east of Lancaster Avenue. This option would eliminate the relatively closely spaced signals on Lancaster Avenue. US 422 mainline would be realigned to run down the center, in the location of the existing ramps. On-ramps and off-ramps would merge and diverge from the right lanes along US 422 removing the problems associated with left entrance and exit ramps.
The PA Route 10 and Lancaster Avenue intersection would be a full movement intersection with this option. Left turns would be provided for the northbound approach of PA Route 10 to accommodate traffic heading south on Lancaster Avenue. This option would require widening of Lancaster Avenue throughout the interchange area, including across the Bingaman Street Bridge. The Thun Trail would be realigned and accommodated through the interchange area. In order to provide the appropriate lane configuration on the north side of the interchange, a reconstruction or replacement of the Bingaman Street Bridge would have to be undertaken. The elimination of the northern signalized intersection on Lancaster Avenue would improve the constructability of the interchange as well as eliminate future issues related to closely spaced intersections similar to the current condition.