Appendix B Highway 407 Interchange Review - Cochrane Street Area

Transcription

1 Appendix B Highway 407 Interchange Review - Cochrane Street Area

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3 AECOM 300 ater Street hitby, ON, Canada L1N 9J2 Memorandum To Michael May, P.Eng., Town of hitby Page 1 CC Subject Greg Hardy, P.Eng., Town of hitby From Brenda Jamieson, P.Eng. / Heather Nottbeck, P.Eng. Date May 24, 2016 Project Number Introduction AECOM was retained by the Town of hitby to undertake conceptual design for potential interchange configurations at Highway 407 and Cochrane Street and Highway 407 and Ashburn Road in the Town of hitby. The approved Highway 407 East plan documented in the 407 East Report includes the following key elements: Construction of the Highway 407 Mainline from Brock Road to Highway 35/115; Construction of two north-south links Highway 412 and Highway 418 that will connect Highway 407 to Highway 401; and Protection for a dedicated transit way and support facilities. The first phase of work (see Exhibit 1) includes a six lane east-west freeway from Brock Road to Highway 412, a four lane east-west freeway from Highway 412 to Harmony Road and a four lane northsouth freeway from Highway 401 to Highway 407. Four arterial road interchanges are planned in the Brooklin area, specifically full interchanges at Lake Ridge Road, Baldwin Street (Hwy 7/12), and Thickson Road, and a partial interchange (to and from the south) on Highway 412 at Highway 7. A full interchange accommodates moves in all directions while a partial interchange only accommodate moves to and from the corridor in one direction. Though not shown in Exhibit 1, the 407 East Report stated: A future interchange at Cochrane Street is not precluded and would be subject to approval of an independent and review and approval by MTO. A conceptual plan of the Town of hitby s proposed interchange at Cochrane Street was included in the Report and is illustrated in Exhibit 2. Cochrane Street is situated approximately 2 km east of Highway 412 and 2 km west of Baldwin Street. Ashburn Road is situated approximately 3 km east of Highway 412 and 1 km west of Baldwin Street. Highway 7 crosses over the Highway 407 corridor midway between Cochrane Street and Ashburn Road. MEMO Highway 407 Interchange Review.Docx

4 Page 2 Memorandum, May 24, 2016 Exhibit 1: Highway 407 East Phase 1 Exhibit 2: Conceptual 407 East / Cochrane Street Interchange Design in 407 East Report

5 Page 3 Memorandum, May 24, 2016 This memorandum provides a brief overview of the key design principles and guidelines that were considered in the development of the conceptual design alternatives for the Cochrane Street and Ashburn Road interchange locations and the identification of key advantages and disadvantages for each alternative design from a design, transportation operations and land use perspective. This memorandum also identifies additional work which is expected to be required by the Ministry of Transportation for their review and approval of an additional interchange on the Highway 407 Mainline between Highway 412 and Baldwin Street. 2. Design Principles and Guidelines The applicable design principles and guidelines for interchange locations and configurations are set out in the Geometric Design Standards Manual for Ontario Highways (GDSOH) and the Highway Access Management Guidelines. 2.1 SYSTEM CONSIDERATIONS An interchange is one element of a freeway system. Freeway design elements and interchange design influence the operation of each other and as such it is essential to treat a length of freeway and its associated interchanges as a single system to ensure proper balance of features and consistent operational quality and performance. Key system considerations include: Interchange location and spacing: Interchanges should be located at major arterial roads in proximity to major development areas. Interchange spacing in urban areas generally ranges from 2 km to 3 km. Coordination of interchanges: Consistency of interchange features in urban areas promotes driver understanding and smooth flowing operation. Right side exits in advance of underpass structures are preferable from a driver expectation and safety perspective. Lane balance and basic lanes: Proper lane balance and maintenance of basic lanes promotes safe operations and accommodates variations in traffic patterns. eaving: hen a freeway entrance is followed by an exit, traffic entering the freeway and that exiting the freeway cross and are in conflict. The conflict between entering and exiting traffic tends to interrupt the operation of through traffic, creates turbulence in the traffic flow and has the effect of reducing capacity and safety performance. This length of roadway is referred to as a weaving section. The weaving length is measured from a point where the adjacent edges of pavement at the merge (on-ramp) are 0.5 m apart to a point where the adjacent edges of pavement at the diverge (off-ramp) are 3.75 m apart as described in Section F.4.5 of the GDSOH. In accordance with the GDSOH, to maintain safe efficient operation between entrance and exit ramps, minimum weaving lengths of 600 m and 800 m should be provided between arterial interchanges and an arterial interchange and a freeway interchange respectively. Shorter weaving lengths may be imposed due to other constraints and will operate with varying qualities of service depending on local conditions such as traffic volumes, sight distance and alignment features. Arterial road interchange locations are typically sited based on the following factors: Interchange spacing guidelines set out in the GDSOH: minimum 2 km spacing between arterial road interchanges through urban areas, providing for a minimum weaving length of 600m;

6 Page 4 Memorandum, May 24, 2016 minimum 3 km spacing between an arterial road interchange and a freeway to freeway interchange, providing for a minimum weavingg length of 800m; Connections to major arterial roadways is preferable; Existing and planned development in proximity to the interchange location; and Traffic forecasting work. As noted previously, shorter weaving lengths and hence a tighter interchange spacing may be accepted by the Ministry if the traffic operations analysis demonstrates acceptable traffic operations can be achieved. 2.2 INTERCHANGEE DESIGN The selection and design of an interchange is influenced by site specific engineering, environmental, topographical and operational considerations. The preferred interchange configuration is the Parclo A4 design as it has the best capacity, operational and safety characteristics relative to other available interchange configurations as shown in Exhibit 3. here significant environmental, geometric or property constraints, alternativee interchange configurations can be considered. Exhibit 3: Comparison of Interchange Configuration Characteristics Interchange Configuration Parclo A4 Parclo A2 Parclo B2 Parclo AB Diamond (1) Characteristic / Selection Consideration Capacity Highest /High /High Delay on Cross Road Low Low Low /High Traffic Progression on Cross Road Best Pedestrian and Bicycle Accommodation on Cross Easy Difficult Difficult Difficult Easy Road Relative Construction Cost High Low Right-of-ay High /High /High /High /Low Note: (1) Partial diamond is a variation of the diamond interchange configuration.

7 Page 5 Memorandum, May 24, 2016 Ramp geometry, including the alignment, profile and cross section, is influenced by a number of design considerations such as traffic volume and traffic mix, geometric and operational characteristics of the crossing road and adjacent through roads, interchange configuration, terrain, traffic control devices and driver expectation. The geometric requirements for interchange ramps are set out in the GDSOH, including applicable design speeds for ramp elements and entrance / exit terminal designs to and from the freeway and the crossing road to satisfy operational and safety performance requirements. The spacing between ramp terminal intersections along the crossing road and adjacent intersections is also an important design consideration with respect to the performance and operation of the ramp terminal intersections. A minimum spacing of 300 m is desirable in accordance with the Highway Access Management Guidelines. A tighter spacing may be accepted by the Ministry if the traffic operations analysis demonstrates acceptable traffic operations can be achieved. 3. Conceptual Design Alternatives Conceptual interchange design alternatives were generated for the Cochrane Street and Ashburn Road locations in accordance with the design principles and guidelines set out in Section 2 utilizing the Highway 407 East issued for construction drawings and base mapping provided by the Town of hitby. 3.1 COCHRANE STREET INTERCHANGE DESIGN ALTERNATIS Given existing site conditions and the design principles and guidelines set out in Section 2, three alternatives were developed for the Cochrane Street/Highway 407 Interchange as follows and shown in Appendix A: Alternative 1 consisting of a Parclo A2 configuration on the north side of Highway 407 (i.e. for the westerly oriented ramps) and a Diamond configuration on the south side of Highway 407 (i.e. for the easterly oriented ramps) which protects for a future eastbound inner loop ramp. This alternative exceeds the minimum weaving distance of 800 m to the Highway 412 interchange ramps and 600 m to the Baldwin Street interchange ramps and provides a separation of 201 m between the south ramp terminal intersection and the Cochrane Street / Highway 7 intersection which is less than the desired minimum spacing of 300 m. Alternative 2 consisting of a Parclo A2 configuration on the north side of Highway 407 (i.e. for the westerly oriented ramps) and a tightened Diamond configuration on the south side of Highway 407 (i.e. for the easterly oriented ramps) which does not protect for a future eastbound inner loop ramp. This alternative exceeds the minimum weaving distance of 800 m to the Highway 412 interchange ramps and 600 m to the Baldwin Street interchange ramps and provides a separation of 215 m between the south ramp terminal intersection and the Cochrane Street / Highway 7 intersection which is less than the desired minimum spacing of 300 m. Alternative 3 consisting of a Parclo A4 configuration on both the north side and the south side of Highway 407. However, due to the proximity of the Highway 412 freeway ramps to the west, the available weaving distance in the westbound direction between the Cochrane Street southbound on-ramp and the westbound exit ramp to Highway 412 southbound would be in the order of 435 m which is well short of the minimum required distance of 800 m. This alternative exceeds the minimum weaving distances to the other adjacent interchange ramps and provides a separation of 201 m between the south ramp terminal intersection and the Cochrane Street / Highway 7 intersection.

8 Page 6 Memorandum, May 24, 2016 Consideration was also given to providing a Parclo B interchange configuration on the south side of Highway 407 for the easterly oriented ramps. However, this configuration would result in a spacing of less than 150 m between the south ramp terminal intersection and the Highway 7/Cochrane Street intersection which was not considered feasible. Furthermore, a Parclo B interchange configuration does not offer the same operational and safety performance as the proposed diamond configuration. The potential for modifications to the Highway 412 interchange easterly oriented ramps was also considered to increase the separation distance to the Cochrane Street interchange. However, given the complexity of the Highway 412 interchange, minor refinements to the easterly oriented ramps are not feasible to increase the separation distance. Key advantages and disadvantages of the Cochrane Street interchange design alternatives are identified in Exhibit 4. Exhibit 4: Key Advantages and Disadvantages of Cochrane Street Interchange Design Alternatives Alternative Advantages Disadvantages Cochrane Street Alt 1 (Recommended for Future Review) Cochrane Street Alt 2 (Recommended for Future Review) Achieves minimum spacing to Baldwin Street interchange (2 km) Standard interchange configuration and geometry; protects for future eastbound inner loop ramp Accommodates all moves Exceeds minimum weaving lengths (1) Parallel lane exit provided on Cochrane Street to westbound onramp which should result in improved traffic operations on Cochrane Street Achieves minimum spacing to Baldwin Street interchange (2 km) Standard interchange configuration and geometry Accommodates all moves Exceeds minimum weaving lengths (1) Direct taper exit provided on Cochrane Street to westbound onramp which should result in acceptable traffic operations on Cochrane Street Spacing of 2 km to Hwy 412 interchange is less than typical minimum requirement of 3 km Provides intersection spacing of 201 m on Cochrane Street between south ramp terminal intersection and Hwy 7 intersection vs desired minimum of 300m Approach grades on Cochrane Street in vicinity of Hwy 407 crossing are approx. 6%; profile adjustments will be required to achieve maximum 3% grade required for ramp terminal intersections Requires widening of watercourse structures east and west of Cochrane Street (M37 and M39) Moderate footprint requirement relative to other alternatives (approx. 12 ha) Moderate cost relative to other alternatives Spacing of 2 km to Hwy 412 interchange is less than typical minimum requirement of 3 km Precludes addition of eastbound inner loop ramp Provides intersection spacing of 215 m on Cochrane Street between south ramp terminal intersection and Hwy 7 intersection vs desired minimum of 300m Approach grades on Cochrane Street in vicinity of Hwy 407 crossing are approx. 6%; profile adjustments will be required to achieve maximum 3% grade required

9 Page 7 Memorandum, May 24, 2016 Alternative Advantages Disadvantages for ramp terminal intersections Requires widening of watercourse structures east and west of Cochrane Street (M37 and M39) Moderate footprint requirement relative to other alternatives (approx. 12 ha) Lowest cost relative to other alternatives Cochrane Street Alt 3 (Not Recommended for Future Review) Achieves minimum spacing to Baldwin Street interchange (2 km) Standard interchange configuration and geometry Accommodates all moves Exceeds minimum weaving lengths to Baldwin Street ramps and the Hwy 412 EB on-ramp (1) Direct taper exit provided on Cochrane Street to westbound onramp which should result in acceptable traffic operations on Cochrane Street Spacing of 2 km to Hwy 412 interchange is less than typical minimum requirement of 3 km Does not achieve minimum weaving length to the Hwy 412 B off-ramp (435 m vs 800 m) Provides intersection spacing of 201 m on Cochrane Street between south ramp terminal intersection and Hwy 7 intersection vs desired minimum of 300m Approach grades on Cochrane Street in vicinity of Hwy 407 crossing are approx. 6%; profile adjustments will be required to achieve maximum 3% grade required for ramp terminal intersections Requires widening of watercourse structures east and west of Cochrane Street (M37 and M39) Largest footprint requirement relative to other alternatives (approx. 14 ha) Highest cost relative to other alternatives Notes: 1. Traffic analysis required to confirm operational performance of weaving sections acceptable. 3.2 ASHBURN ROAD INTERCHANGE DESIGN ALTERNATIS Given existing site conditions and the design principles and guidelines set out in Section 2, one alternative was developed for the Ashburn Road/Highway 407 Interchange as follows and shown in Appendix A: Alternative 1 consisting of a Partial Diamond configuration accommodating movements to and from the west. The entrance to Highway 407 westbound is via a direct on-ramp from Highway 7 westbound, just west of Ashburn Road. The second entrance to the highway for northbound traffic on Ashburn Road is via a loop ramp situated south of Highway 7. The eastbound diamond off ramp tees into Ashburn Road. Consideration was given to the provision of a Parclo A4 configuration on both the north side and the south side of Highway 407. However, given the close proximity of the Baldwin Street interchange to the east and Highway 7 to the north, a Parclo A4 configuration is not feasible at this location. The entrance and exit ramps between Ashburn Road and Baldwin Street would overlap. The separation between the north ramp terminal intersection and the Highway 7 / Ashburn Road intersection would be in the order of 100 m.

10 Page 8 Memorandum, May 24, 2016 Reconfiguration of the Baldwin Street interchange was also considered to assess the feasibility of broadening the range of interchange designs for the Ashburn Road location. However, even with the provision of a Parclo AB interchange configuration at Baldwin Street which situates all the ramps on the east side of Baldwin Street, it is not possible to achieve the minimum weaving lengths since Ashburn Road and Baldwin Street are situated less than 1 km apart. Furthermore, notwithstanding the significant cost and time involved to redesign and reconstruct the Baldwin Street interchange, a Parclo AB interchange configuration at Baldwin Street does not offer the same operational and safety performance as the currently constructed Parclo A4 interchange and may negatively impact on planned transitway infrastructure at Baldwin Street. Key advantages and disadvantages of the Ashburn Road interchange design alternative are identified in Exhibit 5. Exhibit 5: Key Advantages and Disadvantages of Ashburn Road Interchange Design Alternative Alternative Advantages Disadvantages Ashburn Road Alt 1 (Not Recommended for Future Review) Achieves minimum spacing to Hwy 412 interchange (3 km) Exceeds minimum weaving lengths to Hwy 412 ramps (1) Accommodates partial moves only (to and from the west) Non-standard interchange configuration with on-ramps provided from different arterial roads Spacing to Baldwin Street interchange is less than typical minimum 2 km requirement (i.e. 1 km); however weaving is not an issue as there are no easterly oriented ramps Approach grades on Ashburn Road in vicinity of Hwy 407 crossing are approx. 6%; profile adjustments will be required to achieve maximum 3% grade required for ramp terminal intersection Requires widening of watercourse structure and Highway 7 structure east of Cochrane Street and Ashburn Road structure Moderate footprint requirement relative to other alternatives (6 ha) Low cost relative to other alternatives Notes: 1. Traffic analysis required to confirm operational performance of weaving sections acceptable. 4. Next Steps On the basis of the conceptual review documented in this memorandum, an interchange at Cochrane Street is preferred as it better complies with MTO design principles and guidelines, subject to further review including traffic operations analysis. The following additional work is expected to be required to obtain MTO approval of an additional interchange on the Highway 407 Mainline between Highway 412 and Baldwin Street:

11 Page 9 Memorandum, May 24, 2016 Demonstrate the need for an additional interchange: On the basis of the transportation modelling and assessment work undertaken for the 407 East, it was determined that the proposed interchanges at Lake Ridge Road and Baldwin Street and the north-south crossings of the 407 East transportation corridor through this area have sufficient capacity to accommodate the projected 2031 traffic demands. The Town of hitby will need to demonstrate to the Ministry why an additional interchange is required to serve the planned development in the Brooklin area. Traffic operations analysis: Traffic operations analysis will be required to demonstrate that the introduction of an additional interchange on the Highway 407 mainline between Highway 412 and Baldwin Street will not negatively impact the capacity and operation of the Highway 407 mainline and the adjacent interchanges. Feasibility Study: It would be beneficial to conduct a feasibility study to confirm feasible interchange design alternatives from a capacity, operations and safety perspective taking into consideration potential land use and environmental impacts and obtain Ministry support for a new interchange prior to proceeding with a Class Environmental Assessment Study. Class Environmental Assessment Study: A Class Study will be required to obtain environmental clearance for a new interchange between Highway 412 and Baldwin Street. The study should examine, as a minimum, the need and justification for a new interchange and the impacts of the proposed changes on the footprint, capacity and operation of the Highway 407 mainline and the adjacent interchanges. The study should also include mitigation measures acceptable to the Ministry that would address any impacts to the Highway 407 mainline and adjacent interchanges. The technically preferred alternative and associated design will require MTO endorsement as part of the study process. As stated in the 407 East Report, the following key constraints will need to be addressed to MTO s satisfaction when reviewing future interchange proposals at Cochrane Street: The 4.9% grade of Cochrane Street is greater than the MTO maximum standard grade of 3.0% for ramp terminal intersections; The design speed of Cochrane Street would need to be reduced from 80 km /h to km/h to satisfy turning sight distance criteria at the south ramp terminal; The intersection spacing of ramp terminals and Cochrane Street / Highway 7 (approximately 250 m) will be less than the minimum MTO standard of 300 m; The MTO standard for interchange spacing is 3-8 km between arterial and freeway interchanges. Cochrane Street is 2 km east of the est Durham Link Interchange (Highway 412). As noted in previous sections of this memorandum, tighter interchange and intersection spacing may be accepted by the Ministry if the traffic operations analysis demonstrates acceptable traffic operations can be achieved. ith the urbanization of the Cochrane Street area, interchange spacing in the 2 km to 3 km range would comply with typical MTO guidelines. Further, a reduced speed limit on Cochrane Street should be in keeping with the urbanizing condition for the area. Modifications to the Cochrane Street profile will be required to the north and south of the Highway 407 bridge to achieve an acceptable grade on Cochrane Street through the ramp terminal intersections.

12 Page 10 Memorandum, May 24, 2016 Appendix A Conceptual Interchange Design Alternatives

13 NO RT H Lane NG NG Cochra n m e Stree t Country M37 B 2 50 R R = 55 N/ AM S- P N/ P E-N/S S Ashbu RAMP M RA PO FU TE N RA TUR TIA M E L 55 P RAMP N/S-E m Highwa y7 rn Roa d M37 EB Cochra ne Street Lane m Country M39 B M39 EB Highw 0m 91 ay 7 G N 0m 74 G N

14 NO RT H Lane NG NG Cochra n m e Stree t Country M37 B 2 R 50 R = 55 N/ AM S- P 13 rn Roa d M37 EB 0 S E-N/S -N/ P Ashbu RAMP M RA RAM P N/S -E m Highwa y7 Cochra ne Street Lane m Country M39 B M39 EB Highw 0m 91 ay 7 G N 5m 74 G N

15 NO RT H Lane e Stree M37 B M37 EB 50 RAMP N/S R RA =55 S- MP 13 rn Roa d 10 0 RAMP M RA E-N/S -N/ P RA N MP -E 5 S Ashbu NG Cochra n NG Highwa y RAMP N/S-E m Cochra ne Street Lane m Country 910 m t Country 435 M39 B M39 EB Highw 0m 91 ay 7 G N 0m 74 G N

16 NO RT H t E AV E e Stree 5k m NG Cochra n 1. 2 M37 B t Ashbu E AV EL EN GT H e Stree Highway 7 M39 B RA MP E M39 EB 54m Highw ay 250 RAMP RA M P 55 S -N/S 13 0 n Road BA RA LD MP IN - BN N/S A shb ur 1k m Cochra n 2.0 rn Roa d M37 EB BA RA LD MP IN N- BN S 7