Cache County Western Corridor Study
A multi-modal western corridor to help accommodate the future growth of Cache Valley
The study looked at a multi-modal western corridor to help accommodate the future growth of the Cache Valley and help alleviate traffic, but also to provide an option for the future growth west of Logan to have a corridor that they could use to traverse the county. Multiple alignments, roadway facility types, and horizon years were analyzed to provide a better understanding of where, what, and when a corridor would provide the most benefit to western Cache County.
Study Background
Past Plans
The idea of having a western corridor has been on the MPO’s plan for the 2011, 2015, and the must current Draft 2019 Highway Vision Plans
In this Phase 1 draft from 2011, the western corridor is labeled as #6 in blue and runs from just west of Nibley through Amalga on the north.
Past Plans
In this Phase 2 Draft from 2015 the same roadway is shown as stopping at Amalga.
Past Plans
In the latest 2019 Phase 3 draft, the western corridor labeled as #41 and #42 is shown in green with some modification to the alignment where it meanders east and then further west.
In each of these phases of the draft, the corridor has been kept as a low priority. Traffic analysis of this corridor would provide an idea of when a future corridor would be needed.
Existing Conditions
Existing Traffic
Today, traffic in Cache County primarily uses Main Street to connect south U.S. 89 to north U.S. 91. Another corridor that is used within Logan city to travel north-south and circumvent downtown is 1000 West. While this road carries 13,000-17,000 vehicles per day, it cannot be extended further north due to constraints, such as the airport. Main Street through downtown carries between 37,000 – 45,000 vehicles per day, showing that it is a primary regional route for both Logan City and Cache County.
Land Use
Currently much of the study area is zoned as agricultural or public land. This would be the area where the corridor would be built. Much of the residential areas are to the south of S.R. 30 or east of 1000 West. Amalga and Smithfield to the north also have a big area zoned as residential.
Bike Trails
The plan is that when the western Cache corridor is constructed, that a trail will be built adjacent to it. Here you can see that there are a few routes which provide bike facilities, with the majority being a shoulder bikeway. Currently there are many gaps in the trail network, with shoulder bikeways being low comfort. Having a dedicated trail for active transportation would provide high comfort infrastructure for bicyclists and other users.
Future Growth
Household and Jobs Forecasts
Cache County has grown over the past decade and is expected to continue to grow in the decades to come. As shown in the graphs, West Cache County growth is more modest than the greater Cache County, which includes Logan. While this can be expected, West Cache County is where the corridor would be constructed.
Future Growth - PM Peak Hour volume / capacity (v/c) Ratios
The corridor was divided into four sections for volume summary:
Segment 1: US-89 to 600 South
Segment 2: 600 South to SR-30
Segment 3: S.R. 30 to Airport Rd
Segment 4: Airport Rd to SR-218
Segment 2 shows to be the most attractive segment carrying 32,000 vehicles per day. Even with the corridor, Main St through downtown Logan shows congestion.
In addition to this alignment, other possible alignments will be reviewed as part of this study. Additionally, there are many challenges that would need to be considered before refining the alignment.
Challenges
Wetlands
One of the biggest challenges the region faces is the impacts to wetlands. As shown on the map, any corridor that traverses through the study area will be constrained by the valley's wetlands.
Floodplains
Generally, there is not a high flood risk throughout the area, but the alignment may cross some areas where potential flood hazards (shown in red) exist.
Railroads and Utilities
The study area contains electrical lines, railroads, canals, and pipelines. A future corridor will likely cross electrical lines and canals, which may require relocation or additional infrastructure.
Future Land Use
As Cache County grows, land use can change. Most of the available space for development is located west of Logan. This figure shows the future changes in land use for the area where the corridor would traverse. In comparing alignment options, land use would impact where trips are coming from in the study area.
Options
Potential Grid Network
Using the existing roadway network, a planning exercise looked at a grid network to see where optimal road spacing would be based on best planning practices for connectivity. This included Principal Arterials at 2-4 mile spacing and Minor Arterials at 1 mile spacing. However, with the development constraints this grid will ultimately need to be "right-sized" and strategically applied.
Alignment Options
Multiple alignments west of downtown Logan were analyzed looking at how far the future corridor needs to be from 1000 West to draw enough traffic to be effective. The increments were at 1600 West, 2400 West, 3200 West, and 4000 West. These alignments would connect U.S. 89 to S.R. 218.
Additionally, four facility types were used to compare the resulting daily demand of the corridors. The four facility types were:
5-lane Arterial
Expressway with ~1/2 mile signal spacing
Expressway with ~1 mile signal spacing
Freeway
1600 West Alignment – 5-lane Arterial
The alignment at 1600 West, being the closest to downtown, attracts more traffic than the other alignments. The highest demand segment is between 600 South and S.R. 30, which carries 33,000 vehicles per day. The lowest demand segment is the northernmost segment north of the airport, which carries 17,000 vehicles per day.
2400 West Alignment – 5-lane Arterial
The alignment at 2400 West carries less traffic than the alignment at 1600 West, with the segment between 600 South at S.R. 30 carrying 25,000 vehicles per day. The northernmost segment also carries less volume, with 10,000 vehicles per day.
3200 West Alignment – 5-lane Arterial
The 3200 West alignment reduces the amount of demand there is for the corridor, with the highest volume segment carrying 19,000 vehicles per day and the lowest volume segment carrying 7,800 vehicles per day.
4000 West Alignment – 5-lane Arterial
The 4000 West alignment, which is the option furthest away from downtown Logan, carries the least amount of traffic on the corridor with the highest volume segment carrying 16,000 vehicles per day and the lowest volume segment carrying 7,700 vehicles per day.
Roadway Types
Several types of 4-lane facilities were considered and modeled at different speed limits. The project teams preference was for the 65 MPH separated facility with trails similar to Legacy Highway. Here are the roadway type options:
65-mph Arterial with Barrier
Roadway Types
60-mph Arterial with Barrier
Roadway Types
50-mph Arterial with Trail
Roadway Types
35-45-mph Arterial with Sidewalks
Findings
Daily Volume Summary
A threshold of 20,000 vehicles per day was used to determine if a 5-lane facility would be needed to accommodate demand. The graph shows the four different facility types for each of the four alignments south of S.R. 30. This summary shows that further east, or closer to downtown Logan, more traffic would use the corridor. Additionally, the faster and higher capacity the facility, the more traffic would use the corridor. In both the 1600 West and 2400 West alignments, the expressway option (1 mile spacing of signals) attracted more traffic, even greater than the freeway option.
Expressway Alignment
Since the Expressway (1 mile signal spacing) attracted the most traffic, the summary for daily traffic volume south of S.R. 30 is shown in the graph. Here it can be seen clearly that even with a high-capacity facility, demand decreases as the corridor moves further west.
Horizon Years Comparison
2030, 2040, and 2050 horizon year analysis was performed on the 5-lane arterial.
By 2030, none of the alignments met the threshold for a 5-lane facility. Due to its proximity and low volume demand from the previous analyses, 4000 West was not included in this graph.
By the year 2040, both the 2400 West and 1600 West alignments meet the threshold. The reason why 2400 West attracted more traffic when compared to 2050 is that there are projects currently in the Regional Transportation Plan that are phased to be constructed between the years of 2040 and 2050. After the projects are constructed, they will reduce the demand of the corridor at 2400 West.
The arterial met the 20,000 vehicles per day threshold for a 5-lane facility by 2050 for the 1600 West alignment.
Meeting PDFs
Next Steps
The next steps involve conducting more comprehensive planning and analysis. This will require undertaking in-depth assessments of various aspects, including environmental factors and land-use considerations. By delving deeper into these areas, we can gain a clearer understanding of the project's viability and the optimal approach to its development. Through rigorous examination, we will be able to refine our plans, evaluate potential challenges, and identify suitable alignments that align with the project's objectives. These essential next steps will lay the foundation for a well-informed and strategic decision-making process as we move forward in shaping the facility and determining the most suitable alignments.
