TRANSPLAN50 GOAL 1

Update the Regional Highway System to a Metropolitan Grid-Based Network

HISTORIC HIGHWAYS CONNECTIONS AND DEVELOPMENT

Historic Highway Connections

To understand how Utah County’s regional highway network developed, one can look to its neighbor to the north. Salt Lake County grew from downtown Salt Lake City outward establishing regional transportation corridors with well spaced and sized highways.

Utah County has a more rural focused highway system. Its history started with nodal settlements with each town focusing on its own road systems. The state built the main connecting highway between the cities. As the towns grew and began adjoining each other, the proper sizing and spacing of regional highway connections, in most cases, did not occur – the local street network was not complemented by a regional grid.

"Because a connected regional highway grid did not develop as the county urbanized, some developed areas could be impacted to make the connections needed for future growth"

NEW, DEVELOPING AREAS

Rural, greenfield areas on the fringe urban development usually grow slowly, until seemingly overnight, they explode with new development that does not account for nor contribute to an efficient grid system. Congestion starts overwhelming the few existing through streets and highways. Immobility replaces mobility as congestion worsens. Vast areas end up saddled with the consequences of an uncoordinated transportation system.

The northern area in the county, for example, has experienced high growth with limited highway connections. East-west corridors between American Fork Main ST and Timpanogos HWY are nonexistent. Main Street has a much higher than normal traffic burden. Timpanogos Highway had to be over-built to almost a freeway-type standard to compensate for the lack of an area grid network. With future growth pushing outward, the western and southern areas of Utah County are now at most risk for impacts on developed areas for not having a connected grid network built with growth.

CONGESTED CHOKEPOINT AREAS

Transportation Choke Points
Utah County has a unique geography with its towering mountains, lakes, and wetlands. These features create a unique geographic environment making transportation connections a challenge. In the county, there are five areas where transportation corridors must traverse within narrow strips of land bordered by these features called transportation choke points.

LINDON CHOKE POINT
The Lindon Choke Point today has the highest traffic volumes in the valley with a significant commuter movement between the central and northern areas of the county.

With only three highway corridors, State Street, I-15, and Geneva Road, as well as FrontRunner Commuter Rail, this is an important area to focus on relieving congestion. TransPlan50 proposes improvements to 1-15 and commuter rail in this area as well as the addition of light rail and bus rapid transit along State Street.

DESIGNING A REGIONAL HIGHWAY GRID NETWORK

Regional Highway Grid Spacing
Recognizing the challenges greenfield areas face as they urbanize, the Institute of Transportation Engineers (ITE) created a Best Practice recommendation for macrolevel network spacing, that if adhered to, would minimize congestion on any given facility. The thought is that having a grid of properly spaced roads that can handle different types of trips (local to sub-regional to regional), that traffic would be spaced out easing congestion and dispersing traffic more evenly throughout the area avoiding placing all traffic on just a few major corridors. The hierarchy of a regional highway network starts with Freeways and Expressways. These corridors are the highest mobility corridors have characteristics that include grade-separated interchanges (Expressways can have signaled intersections), higher traffic volumes, higher speeds, limited access, and are ideally 5 miles apart. Principal Arterials are the higher mobility corridors carrying regional traffic, high volumes, generally have controlled access (fewer driveways), and higher speeds. Minor arterials have lower speeds and more access points. Collectors have lower volumes and even more access.

HOW TO DESIGN THE HIGHWAY GRID SYSTEM

MOBILITY VS. ACCESS

HOW IT WOULD LOOK OVERLAYED OVER UTAH COUNTY

ITE HIGHWAY GRID SPACING OVER UTAH COUNTY

“A Highway Grid is not just a network of perpendicular roads. It can have bends and curves. It’s all about right sizing, proper access, connections and spacing”

PROPOSED UTAH COUNTY GRID

To create a grid network of arterial and collector highways in Utah County, MPO staff worked with municipal staff to draft a plan that allows for properly spaced corridors within greenfield and developed urban areas. In many cases corridors within the developed areas are mostly complete. What is needed are connections to adjoining roads in neighboring municipalities. Some proposals would require little to no neighborhood disruption; others could be more complicated. The proposed grid plan is a starting place to begin the discussion. The proposal is to work with each municipality and the county through their planning processes to vet what corridors can work, what corridors would need adjustment, and what will not work.

It is estimated that completing the countywide urban grid network as proposed requires an additional 1,000 miles of new lanes. A quarter of these lanes are in current built-up urban areas with the remainder in greenfield areas. The proposed grid also removes about 750 structures, more than half of which are located in rural areas and will most likely be incorporated into future developments. The total cost of the grid network is estimated at upwards of $2 billion dollars, not including projects already proposed and funded in TransPlan50. Of this cost, $500 million is anticipated within the built-up urban areas. Most of the $1.5 billion to build the grid in the rural areas will be funded by private development if properly planned for. Moving forward, MAG will work with our stakeholders to identify which projects can be adopted into municipal and regional plans. More importantly, funding to construct the collectors proposed in the grid network will have to be identified. Currently, only local and regional funds can be used in funding these types of facilities, with these funds already stretched thin. State-wide solutions will most likely need to be sought to these regional non-state-owned roads in the future

BENEFITS OF A CONNECTED HIGHWAY GRID

Benefits of a Connected Highway Grid
The benefits of relieving regional congestion by completing the grid network are high. With the proposed growth to 2050, overall travel delay in the region increases elevenfold compared to 2018. To put this in perspective, Salt Lake County in 2018 had five times more congestion related delay than Utah County. Modeling shows that with a connected arterial and collector grid network with no additional freeways, the 2050 travel delay would only grow to seven times that of today. With the addition of the proposed freeways in the plan, congestion rises to only three times the current delay, well within acceptable limits of a metropolitan area of 1.3 million people.

11X

More Delay than Today

Utah County
Without Grid

5X

More Delay than Utah Co

Salt Lake County
Today

2X

More Delay than Today

2040 Utah
Co Goal

TRAVEL TIME DELAY

Travel Time Delay
Another way to understand future network conditions is with travel time. In 2018 a trip by automobile between Eagle Mountain and Provo took about 39 minutes. With no improvements, by 2050 the same trip takes 1 hour and 16 minutes; Provo to Payson 18 minutes versus 1 hour, and Lehi to Salt Lake City 41 minutes versus 1 hour.

“Congestion increases exponentially without system improvements”

DISPERSING TRAFFIC

The reason a network of arterial and collector roads works is its ability to spread out traffic. Today the North and Central areas are connected by three main corridors, all state routes; I-15, State Street (US-89), and Geneva Road (SR-114). By creating additional connections of smaller roads in this area, localized trips would no longer be required to traverse the major roads, thereby reducing congestion. Connecting collectors and arterials does not necessarily lead to heavy traffic on these roads, rather, by spreading trips out, the total volumes of traffic on a single corridor can be reduced.