U.S. Roads & Highways Remain Central to Mobility’s Future

In addition to passengers, the region’s roadways carry freight cargo, public transportation, as well as support bicycle travel. Roadways will remain the primary means for the region’s travel needs, while we find ways to reduce vehicle miles and hours traveled. The goal: reduce congestion and improve air quality.

Region Roadway Network

The OKI region has more than 12,000 miles of roadways, which transport both passengers and goods via private automobile, taxi, bus, bicycle and truck. This amounts to traveling about 50 million vehicle miles a day.

National Highway System

The core of the roadway network is this region’s component of the National Highway System (NHS). There are 2,516 lane miles of the NHS carrying more than half of the daily traffic within the OKI region.

The NHS within the OKI region includes: I-71; I-74; I-75; I-275; I-471; US 27 (in Ohio, north of I-74); In Kentucky, between the Ohio state line and I-471 in Southgate and between I-471 in Highland Heights and SR 9); KY 8 (between I-71/75 and I-471); KY 9 (the AA Highway) in Kentucky; SR 4 (north of I-75); SR 32 (east of I-275); SR 125; SR 126 (Ronald Reagan Highway); SR 129 (Butler County Veterans Highway); and SR 562 (Norwood Lateral) in Ohio.

Scenic Byways

At the other end of the roadway network spectrum are scenic byways. These distinct and diverse roadways strengthen the tourist industry’s contribution to the region’s economy. Scenic routes are valued and even designated for driving pleasure. Moreover, these routes help preserve communities and the surrounding countryside.

Five scenic byways exist within the OKI region:

  • Ohio River Scenic Byway in Indiana
  • Ohio River Scenic Route in Ohio
  • Accommodation Line Scenic Byway
  • Big Bone Lick – Middle Creek Scenic Byway
  • Riverboat Row Scenic Byway

Strategies to Address Existing Roadway Needs

Several strategies for improving mobility, connectivity, congestion and safety are available options. These should be explored before recommending new or expanded roadway facilities, due to financial, environmental and social impacts.

This plan has identified roadway improvement projects for addressing mobility through and within the region on existing roadways. Operation and maintenance projects (O&M) are not specifically identified in this plan. However, they are consistent with the goals of the 2050 Plan.

Preservation and Rehabilitation

The 12,000-plus miles of the region’s roadway are expected to continue to provide service throughout the life of the 2050 Plan. Reconstruction projects are needed to preserve and maintain the roadway system. This plan gives funding priority to system preservation and allocates a sizeable portion of available revenues to this purpose.

Operational Improvements

Regardless of the type of roadway facility, operational improvements can enhance the mobility and safety of travelers in the OKI region. Most improvements can be made relatively quickly and at lower costs than capacity projects. Many of the plan’s recommended roadway projects incorporate operational improvements as a means of addressing mobility, congestion and safety needs. This includes such measures as restriping bike lanes, crosswalks near transit stops, and filling in existing sidewalk gaps.

Several operational improvements already have been made throughout the OKI region, including access management, improved signalization, roundabouts, continuous flow intersection, single-point urban interchanges and active travel demand management.

Several operational improvements already have been implemented throughout the OKI region, including:

Access Management

Access Management involves the design, operation and location of driveway and street connections onto a roadway. Control is achieved by public plans or policies aimed at preserving the functional integrity of the existing roadway.

Access management is fundamental to preventing mobility and safety problems caused by multiple curb cuts and traffic signals. According to the Federal Highway Administration (FHWA), the application of access management along urban and suburban arterials can reduce fatal and injury crashes by as much as 31%.

By enabling roadways to perform more efficiently, access management increases roadway capacity that may reduce the need for expansion projects; and it could help preserve and maintain existing infrastructure.


Signalization is often an effective means of improving traffic flow in developed corridors. Since computerized traffic signal systems were introduced in the late 1970s, options have increased for reducing congestion by applying and coordinating progressive signal systems — as exemplified by closed loop systems.

On a corridor, area-wide or multi-jurisdictional basis, centralized networks may involve hundreds of signalized intersections. The benefits of improved signal systems are commonly measured by reductions in travel time, vehicle stops, delay, fuel consumption, emissions and increases in travel speed.


Roundabouts are smaller, modified versions of traffic circles or rotaries. They have been used in Europe for decades and, to a lesser extent, in the New England states. Roundabouts require drivers to yield on entry to vehicles already in the roundabout. Modern roundabouts are specifically designed to reduce speed as vehicles approach and enter.

Roundabouts require clear signage and pavement markings. They are proving to be safe, effective and efficient alternatives to signalized or stop sign-controlled intersections. And their use is expanding rapidly. There are at least 80 in the OKI region and several others are in the design phase. Local jurisdictions are considering them as a cost-effective alternative to signalized intersections.

Double Crossover Diamond Interchange

A double crossover diamond interchange (DCD) is one designed to ease congestion, reduce accidents and save money. The DCD is a variation of the conventional diamond interchange in which the opposing directions of travel on the non-freeway road cross each other on either side of the interchange. This is so that traffic crossing the freeway on the overpass or underpass is operating on the opposite driving side from that which is customary for the jurisdiction.

The geometric design channelizes vehicular traffic on a grade-separated crossroad from the right side of the road to the left side and then back again at the ramp terminals. This eliminates the need for drivers to turn left in front of oncoming traffic, which is a common cause of accidents at conventional diamond interchanges.

The first DCD in the United States was opened in Springfield, Missouri, in 2009. Since then, DCDs have been built in over 100 locations across the country. Recently, KYTC built DCDs at the Mt. Zion and Richwood Road Interchanges at I-71/75 in Boone County.


Single-Point Urban Interchanges

Single-Point Urban Interchanges (SPUIs) are a variant of the conventional diamond highway interchange. SPUIs result in two signalized intersections at the points where the entrance and exit ramps meet with the cross street. Due to the relative close spacing of such intersections, efficient signal timing is often difficult to achieve. This problem is eliminated by SPUIs through the creation of one large intersection, either directly above or below the freeway.

This intersection design creates a situation where drivers are only faced with cross-street traffic, and either exiting roadway or entering left-turning vehicles. The exiting right-turning vehicles are accommodated on separate free-flowing ramp segments. Efficiencies are achieved because paired left-turn movements can be accommodated simultaneously, and the signal phasing can be reduced from four to three phases, allowing more green time for each phase.

The KY 18 and KY 237 interchange in Boone County is a local example of a SPUI.

Transportation Demand Management Roadway Strategies

Active Traffic Demand Management (ATDM) is a collection of techniques that provides both operational improvements and temporary capacity enhancements without adding new lanes to freeways. ATDM applications or strategies can be used in concert with other applications to provide spot improvements as well as overall corridor benefits.

ATDM systems use a variety of sensors and human operators at the Traffic Management Center (TMC) to collect traffic data. This data can be processed and used to activate roadside systems in near real‐time, which then dynamically manage traffic based on prevailing conditions.

Types of ATDM strategies that may be considered:

  • Ramp Metering
  • Hard Shoulder Running
  • High Occupancy Vehicle (HOV) Lanes
  • Truck Only Lanes
  • Contra Flow Lanes
  • Choice Lanes
  • Dynamic Merge Control
  • Dynamic Lane Assignment
  • Variable Speed Limit/Speed Harmonization
  • Queue Warning

Transportation Demand Management Roadway Strategies (TDM) focus on changing travel behavior to ease traffic congestion in lieu of building infrastructure to support travel needs. Specifically, TDM strategies encourage alternatives to SOV travel and shifting trips out of peak travel periods — or even eliminating some trips altogether. Ramp metering, dynamic lane assignment, variable speed limits and queue warnings have been used in the OKI region.  

New or Expanded Roadway Capacity Improvements

The OKI Congestion Management Program offers options most suitable for locations identified as congested. However, an unacceptable level of congestion will remain in some areas due to deficiencies in roadway capacity. These are areas where new or expanded roadway capacity is needed. Projects that add capacity are required to be specifically identified and subjected to air quality conformity analysis. This plan has recommended 53 projects with new or expanded roadway capacity.

Recommended Roadway Projects

Beyond the value of the TIP, this plan includes 167 roadway projects totaling $6.7 billion. The cost of these roadway recommendations accounts for about 66% of the plan’s total number of 284 fiscally constrained projects. This cost includes the Brent Spence Bridge project divided by Ohio and Kentucky’s portions. The replacement of the Brent Spence Bridge, which carries I-71 and I-75 traffic, is vital to the region’s success and is highly recommended.

The list of recommended roadway projects is fiscally constrained, meaning the expected available funding is sufficient to construct or implement them. (Fiscal constraint is discussed in more detail separately.) The plan’s fiscally constrained roadway projects include a total of 12 miles of new roadway and 134 additional lane miles throughout the region. A breakdown of recommended roadway improvements by project type is listed below.

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