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Prepared by: |
Town of Lacombe |
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1.0
Introduction 1.1 Background The Town of Lacombe has a current population of approximately 8,500. It has been experiencing strong growth in recent years with an average annual growth rate of over 3%. Most of this population growth has been accommodated in the north area of Lacombe. The Town last had a comprehensive transportation study completed in 1990. The Heritage Area Traffic Study was undertaken in 1997 in anticipation of continued residential growth in the north part of Lacombe. This study, while primarily focused on transportation issues, in the north part of the Town, did identify the Highway 2A/Highway 12 intersection as a continuing area of congestion. Earlier this year, due to constraints in continuing
development in north Lacombe, the Town revised its land use plans in
order to permit residential development in the area south of Highway 12
and east of Highway 2A. This represented a substantial change in land
use patterns from that previously considered by the Town. The impacts of
this decision on the Town’s transportation network and on Highway 2A
in particular were not fully understood and the Town felt a traffic
study to address this issue was warranted. In addition to this longer
term planning issue, the Town was also considering developing in the
short-term the land between Highway 2A and the CPR tracks south of
Highway 12 (50 Avenue) for commercial uses. Again, the impacts of this
decision on Highway 2A were not fully understood and Alberta
Transportation & Utilities suggested that the Town undertake a
traffic study to address both of these issues at one time. The Town then
retained Stantec Consulting Ltd. to complete a traffic study for Highway
2A between 46 Avenue and Airport Road. Figure 1.1 illustrates the limits
of the Study Area which, during the course of the study, were expanded
to the south to include C and E Trail as a result of the review of the
long-term roadway network requirements.
In order to understand existing traffic conditions, traffic counts were undertaken at number of key locations in Lacombe on Wednesday, 30 September 1998 and Thursday, 1 October 1998 from 15:30 to 18:00. Counts were done at the following locations:
Figure 2.1 summarizes the peak hour turning movement volumes at these intersections. It should be noted that these traffic count volumes are generally lower than those done in the Fall of 1997 as part of the Heritage Area Traffic Study. The primary reason for this decrease is likely related to the 1997 counts being done on a Friday during operation of the farmers’ market. The Heritage Area Traffic Study recognized that the doing the counts on a Friday in September represented one of the busier days for traffic. The counts done as part of this study are considered to reflect more typical peak hour volumes. 2.1.2 Traffic Operations at Intersections Traffic operations are typically defined by the term Level of Service Table 2.1 summarizes the characteristics of the various Levels of Service. Table 2.1 Level of Service Characteristics
The existing traffic operations at unsignalized intersections were analyzed using the Highway Capacity software while the signalized intersection of Highway 2A and Highway 12 was analyzed with the CCG Calc software. The analysis indicated the following:
Typically, Alberta Transportation & Utilities strives to provide a Level of Service C or better on rural Primary Highways. Work completed as part of the Heritage Area Traffic Study identified acceptable delays in a community the size of Lacombe at unsignalized intersections as follows:
These delays generally correlate to a Level of Service B. At signalized intersections the acceptable level of congestion would likely be defined as a Level of Service C. Working in consultation with Town staff, assumptions were developed for the growth of the Town of Lacombe from its current population of approximately 8,500 to a population of 15,000 over the next 20 years or so for two scenarios. The first scenario assumed most of the residential growth would occur in the southeast quadrant of the Town. The second scenario assumed that residential growth would be split between the southeast quadrant and the north area (College lands). Table 2.2 summarizes these assumptions. Table 2.2a Population Assumptions – Scenario 1
Table 2.2b Population Assumptions – Scenario 2
The 1990 Transportation Study identified the PM Peak Hour trip generation rate as 0.20 vehicle trips per person inbound and 0.14 vehicle trips per person outbound. Internal trips (trips with both an origin and a destination in Lacombe) to or from employment areas were assumed to originate from or be destined to residential areas. Through traffic volumes on Highways 2A and 12 were assumed to increase by 2% per year. These assumptions were considered to be still valid. Distribution of the trips generated by future growth in the population base of Lacombe was developed in consultation with Town staff and vetted by Parkland Planning Services. The percentages summarized in Table 2.3 originate from data and assumptions in the 1990 Transportation Study. They have been adjusted to reflect a long-term trend of the percentage of work related trips to employment opportunities outside of Lacombe increasing in relation to work related trips to employment opportunities in Lacombe as well as the continued expansion of employment opportunities in the Joffre area. Some variations in these percentages could be expected if employment and shopping opportunities in Lacombe increase dramatically or if industrial developments in the Joffre area are reduced in scale. Table 2.3 Trip Distribution
The new trips generated by continued growth were assigned to the existing roadway network based on the basis of the shortest origin/destination route. The existing road network was assumed to include the extension of Woodland Drive to Highway 2A opposite Wolf Creek Drive as this link is scheduled for construction in 1999. Figures 2.2, 2.3 and 2.4 illustrate the projected turning movements for key intersections at the 5 year (10,000), 10 year (11,500) and 20 year (15,000) projections for Population Assumptions - Scenario 1 (growth concentrated in the southeast). Figure 2.4a illustrates the projected traffic volumes for the 20 year (15,000) horizon based on Population Assumptions - Scenario 2 (growth split between the north and southeast). Recognizing the likely need for development of other east-west connections, besides Highway 12, to service the proposed residential development in the southeast quadrant, two alternative roadway networks were developed. These networks are illustrated in Figure 2.5 and are as follows:
Figures 2.6, 2.7 and 2.8 illustrate the projected traffic volumes based on Population Assumptions – Scenario 1 (growth concentrated in the southeast) for the three population horizons with creation of a crossing at 48 Avenue. Figure 2.8a illustrates the projected traffic volumes based on Population Assumptions – Scenario 2 (growth split between the north and the southeast) for the 20 year (15,000) horizon. Figures 2.9, 2.10 and 2.11 illustrate the projected traffic volumes based on the Population Assumptions – Scenario 1 (growth concentrated in the southeast) for the three population horizons with creation of the South Bypass. Figure 2.11a illustrates the projected traffic volumes based on Population Assumptions – Scenario 2 (growth split between the north and the southeast) for the 20 year (15,000) horizon. 2.2.5 Highway 2A/Highway 12 Intersection Operational Analysis The projected traffic volumes based on Population Assumptions - Scenario 1 (growth concentrated in the southeast) at the key Highway 2A/Highway 12 for the Existing, Existing plus 48 Avenue Extension and the Existing plus South Bypass alternatives were analyzed using the CCG Calc software. Table 2.4 summarizes the projected levels of service for each population horizon. Table 2.4 Highway 2A/Highway 12 Intersection Operations
(0.62) - volume/capacity ratio From the information presented in Table 2.4, the addition of either the 48 Avenue Extension or the South Bypass to the existing roadway network has little impact on traffic operations at the Highway 2A/Highway 12 intersection. Improvements to the Highway 2A/Highway 12 intersection will be required within 10 years regardless of any other roadway network improvements completed in order to maintain a Level of Service C or better. A number of alternative configuration improvements to the Highway 2A/Highway 12 intersection were evaluated. Recognizing that widening of Highway 12 west of Highway 2A is not practical, due to existing buildings, the alternatives focused on potential improvements to Highway 2A. The most effective alternative was the addition of left turn bays in the north and southbound directions and a right turn lane in the westbound direction. Table 2.5 summarizes the impact of this improvement based on the traffic volumes projected for Population Assumptions - Scenario 1 (growth concentrated in the southeast). For Population Assumptions - Scenario 2 (growth split between the north and the southeast), the Levels of Service at the 20 year (15,000) horizon are better, but not significantly and the conclusions reached remain the same. Table 2.5 Highway 2A/Highway 12 Intersection Operations
(0.62) - volume/capacity ratio The information presented in Table 2.5 indicates that intersection improvements can be used to maintain the Highway 2A/Highway 12 intersection at a Level of Service C or better for a minimum of 10 years without the need for other network improvements. However, maintaining a Level of Service C or better in the longer-term (20 or more years) will require implementation of either the 48 Avenue Extension or the South Bypass alternative. The South Bypass alternative is the preferred alternative for the following reasons:
2.2.6 Highway 2A Cross-Section Requirements For the sections of Highway 2A north of Airport Road and south of 58 Street, the criteria of Average Annual Daily Traffic volumes in excess of 7,000 were assumed to be the minimum to warrant twinning of the highway. Using the projected traffic volumes for the 20 year horizon and an assumed factor of 10 to convert peak hour to AADT, twinning of Highway 2A north of Airport Road (projected AADT of 6,600) will not be warranted in the 20 year horizon. South of 58 Street projected AADT volumes will exceed 7,000 in the 5 to 10 year horizon suggesting that twinning will be warranted before the 10 year horizon. For the section of Highway 2A from 58 Street to Airport Road, the
Highway Capacity Manual software was used to analyze lane requirements
and intersection operations. In general, the cross-sectional
requirements at the 20 year horizon are four through lanes with left
turn lanes at all-directional intersections. The exception is the
section of Highway 2A north of Wolf Creek Drive where the existing
three-lane cross-section (two lanes northbound and one lane southbound)
is adequate for the projected traffic volumes. 3.1 Recommended Long-Term Roadway Network Plan Based on the analysis summarized in Section 2.0, a recommended long-term roadway network plan was developed. Key features of the plan include:
The recommended plan also envisaged the elimination and consolidation of some access points along Highway 2A between 46 Avenue and Woodland Drive. Figures 3.1a and 3.1b illustrate the overall plan. 3.2 Recommended Plan for Highway 2A In order to evaluate how the recommended cross-section and access control could be provided along Highway 2A a number of alternatives were developed. Through a review of the alternatives the following constraints were identified:
To gauge public opinion on the alternatives developed, an Open House was held on 18 March 1999 in the meeting room above the Town Arena. A summary of the Open House is contained in Appendix A. In general, the public feedback indicated the following:
Based on this input and concurrence from Town Council at their regular meeting of 26 April 1999, a recommended plan was developed. This plan was presented to Alberta Transportation & Utilities’ Planning Council at their meeting of 26 May 1999. The plan was accepted by Alberta Transportation & Utilities’ Planning Council subject to a few minor changes to the cross-section. The resulting recommended plan, including a description of the changes requested by AT&U, is described in the following sections. 3.2.2 Recommended Cross-Section South of 46 Avenue, Alberta Transportation & Utilities plans call for Highway 2A to have a rural cross-section with a 20 metre wide centreline separation and a depressed centre median. From just south of 46 Avenue to Airport Drive, the urban nature of the adjoining development and the restricted road right-of-way require that the cross-section of Highway 2A be more urban in nature. Figure 3.4 illustrates the recommended cross-sections for each distinct segment of the roadway. 46 Avenue to 50 Avenue The recommended cross-section in this area is a four-lane divided urban arterial cross-section with 3.7 metre wide lanes and a 6 metre wide raised median. It includes an 11.5 metre wide service road along the west side of the right-of-way to provide access to existing businesses. Parallel parking would generally be permitted along the east side of the service road although in some locations it may be necessary to prohibit parking in order to allow large vehicle access/egress to certain businesses. Except in the immediate vicinity of 50 Avenue, the existing right-of-way is adequate to accommodate the recommended cross-section. The original cross-section presented to Alberta Transportation & Utilities’ Planning Council did not include a raised median, only a left turn lane. Given the adequacy of the existing right-of-way and superior access control that a raised median provides, it was decided that that the cross-section should be widened to allow for a raised median. 50 Avenue to 52 Avenue The recommended cross-section in this area is a five lane undivided urban arterial cross-section. Four through lanes 3.7 metres in width and a 3.5 metre wide left turn lane are provided. The undivided cross-section allows for all-directional access to the existing businesses along the west side to be maintained and minimizes the right-of-way acquisition requirements from the CPR. With the recommended cross-section, 5 metres of road right-of-way widening to the east is required. 52 Avenue to Airport Road The preferred cross-section in this area is a four–lane divided rural arterial cross-section with four 3.7 metre wide through lanes and a 6 metre wide raised median to accommodate 3.5 metre wide left turn lanes at intersections. However, it is recognized that due to the constraint of the existing service roads to the west, 7.5 metres of road right-of-way widening to the west will be required. Acquiring this width of right-of-way from the CPR may be problematic although it should certainly be investigated further. If it is not possible to acquire this much road right-of-way widening, then a five-lane undivided cross-section, with a 3.5 metre wide left turn lane rather than a 6 metre wide median, is recommended. The required 5 metres of road right-of-way widening into the CPR right-of-way is likely to be acceptable to the CPR. 3.2.3 Recommended Access Control Figures 3.5, 3.6, 3.7, 3.8 and 3.9 illustrate the recommended access control and general layout for the recommended plan. 46 Avenue to 50 Avenue (Highway 12) Figure 3.5 illustrates the recommended plan for the section of Highway 2A from 46 Avenue to 50 Avenue. The posted speed limit in this section is envisaged to remain at 50 km/h. All-directional access to/from Highway 2A will be maintained at 48 Avenue, 49A Avenue and 50 Avenue. The recommended plan also envisages extending 46 Avenue to the east to provide all-directional access to Highway 2A opposite 45A Street. A minor realignment of 46 Avenue, east of Highway 2A, will be required so that it aligns properly with the proposed 46 Avenue extension to the west. A right-in/out access to Highway 2A is also recommended at 49C Avenue to provide access to the core of the downtown commercial area and the existing parking area. 50 Avenue (Highway 12) to 45 Street Figure 3.6 illustrates the recommended plan for the section of Highway 2A from 50 Avenue to 45 Street. The posted speed limit in this area is envisaged to remain at 50 km/h. It is recommended that all-directional access to Highway 2A be retained at all intersecting roadways (51 Avenue, 52 Avenue and 45 Street) as well to the existing businesses along the west side between 50 Avenue and 52 Avenue. In the area between 50 Avenue and 51 Avenue it is recommended that the multiple and very wide accesses to the existing businesses be consolidated and joint access be used where possible. Closure of the access immediately north of 51 Avenue is recommended as it is too close to the intersection and another existing access immediately to the north provides adequate access to the existing commercial development. No widening of Highway 12 is contemplated as part of this study. However, to accommodate the proposed improvements at the Highway 2A/Highway 12 intersection, widening of the existing crossing of the CPR tracks will be required. During detailed design the potential impact of this widening on the operation of the switch immediately to the north of the crossing should be reviewed in more detail with the CPR. At present, there is approximately 24 metres between the centreline of west set of CPR tracks and the east edge of Highway 2A. The Stop Bar is located adjacent to Highway 2A and adequate space exists for 2 westbound vehicles to queue at the traffic signals without the queue backing up onto the railway tracks. There is just enough space for a WB-15 semi-trailer (17.5 metres long), but inadequate space for the usual design vehicle (WB-23 semi trailer), which is 25 metres long. On occasion vehicle queues do back up over the tracks. However, it is understood that the traffic signals are interconnected to the railway crossing protection and an east-west clearance phase is provided on the traffic signals to allow vehicles to clear the track crossing before the train arrives. No train-vehicle collisions have been recorded at this crossing in the last 5 or more years. Notwithstanding this collision record, there is concern that the current location of the Stop Bar may increase the potential for a conflict and moving the Stop Bar to the east side of the tracks should be considered. The problem with moving the Stop Bar to the east side of the railway tracks is the large distance across the intersection which will result. An intersection of this width creates operational problems by substantially increasing the required length of the inter-green period (yellow-red), increases the probability of left turning vehicles being stranded in the intersection when the light changes and makes right turns on red more difficult. Experience also suggests that it is difficult to get vehicles to stop some 30 or more metres back from the adjoining roadway and many vehicles will proceed beyond the tracks in any case. Given there is no record of problems at this crossing and that a clearance phase is provided by the traffic signals when a train activates the crossing protection, we do not recommend relocating the Stop Bar to the east side of the tracks. In our opinion, the operational problems relocating the Stop Bar will create outweigh the perceived safety benefits. In the future, the proposed widening of Highway 2A to the west will result in there being approximately 19 metres between the east edge of Highway 2A and the centreline of the west CPR track. Again, in our opinion relocating the Stop Bar to the east side of the railway tracks will result in an excessively wide intersection. With the traffic controlled by a traffic signal that allows for a clearance phase when a train activates the crossing protection, little value is seen in relocating the Stop Bar to the east side of the railway tracks. 45 Street to Airport Road Figures 3.7, 3.8 and 3.9 illustrate the recommended plan for the section of Highway 2A from 45 Street to Airport Road. The posted speed limit is envisaged to remain 70 km/h from north of 45 Street to north of Airport Road. It is recommended that all-directional access to Highway 2A be maintained at Woodland Drive, Wolf Creek Drive (east and west), Dickens Lane and Airport Road. The recommended plan does not illustrate a median in this area, but as noted in Section 3.2.2 and on the plans it would be desirable to provide a 6 metre wide median if adequate right-of-way can be obtained from the CPR. To maintain traffic operations along Highway 2A at a Level of Service C or better as Lacombe grows to a population of 15,000 (approximately 20 years) upgrading of Highway 2A to the recommended plan and development of a south by-pass will be required. The recommended improvements for Highway 2A can be staged over a period of time as the population grows and traffic volumes warrant the improvements. 3.3.1 Stage 1 – 46 Avenue to 51 Avenue As the population of Lacombe grows from its current level of 8,500 to a population of slightly more than 10,000 (5 to 10 years), it is likely that improvements at the Highway 2A/50 Avenue (Highway 12) intersection will be required to maintain a Level of Service C. Concurrent with these intersection improvements, which at a minimum would involve constructing the recommended plan from 49B Avenue to 51 Avenue, it is recommended that the improvements to south of 46 Avenue be constructed. At present, Alberta Transportation & Utilities does not have this section of Highway 2A programmed for pavement rehabilitation within the next 10 years. Due to the existing roadway cross-section and profile, it is unlikely that rehabilitating the existing pavement can be done in a manner such that it would be consistent with the recommended plan. Therefore, should rehabilitation of the existing pavement be required before traffic volumes or operations warrant upgrading of this section, it is recommended that the upgrading be advanced and done instead of the pavement rehabilitation. 3.3.2 Stage 2 – 51 Avenue to Wolf Creek Drive Upgrading of this section of Highway 2A would depend on the rate of development in North Lacombe and traffic operations along this section of the roadway. Widening of Highway 2A to its recommended cross-section is anticipated to be required in the 10 to 15 year period. At present, Alberta Transportation & Utilities does not have this section of Highway 2A programmed for pavement rehabilitation within the next 10 years. However, should rehabilitation of the existing pavement be required before traffic volumes or operations warrant upgrading of this section, it is recommended that consideration be given to advancing the upgrading so that it is done concurrently with the pavement rehabilitation. Doing the two programs concurrently will likely result in some economies of scale. 3.3.3 Stage 3 – Wolf Creek Drive to Airport Road Upgrading of this section of Highway 2A would depend on the rate of development in North Lacombe and traffic operations along this section of the roadway. Widening of Highway 2A to its recommended construction is anticipated to be required in the 15 to 20 year period. At present, Alberta Transportation & Utilities does not have this section of Highway 2A programmed for pavement rehabilitation within the next 10 years. Although not required as part of this traffic study, preliminary cost estimates were prepared to provide general guidance on funding requirements to implement the recommended plan. Table 3.1 summarizes the order of magnitude cost estimates for each of the three recommended stages. The cost estimates do not include the cost of land acquisition, but do assume that the existing storm sewer along Highway 2A south of 50 Avenue is of inadequate depth and capacity to be utilized for the proposed urban cross-section. Table 3.1 Cost Estimates
A breakdown of the quantities and assumed unit prices used to derive these cost estimates is contained in Appendix B. |
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