Continuous Flow Intersection

Intersection & Study Background

The Beechmont Avenue (State Road 125) and Five Mile Road intersection, in the heart of Anderson Township, is consistently one of the most heavily traveled intersections in Greater Cincinnati, and unfortunately is typically one of the most dangerous intersections in Hamilton County. Over 65,000 cars a day travel through this intersection which has historically ranked in the top five intersections with for the total number of accidents. Coupled with this heavy volume and high accident rate, this intersection operates at a level of service E (nearly failing), with an average peak hour delay of over a minute. There is currently no provision for pedestrian traffic; in fact, there are signs prohibiting pedestrian crossing.

Since the intersection is tightly constrained by surrounding development and limited right of way, a major reconfiguration or grade separated interchange has effectively been ruled out. In addition, except for a planned right turn lane from eastbound Beechmont to southbound Five Mile and the concept of a double left from westbound Beechmont to southbound Five Mile, each leg of the intersection is “maxed out” with two thru lanes, a right turn lane, and a left turn lane. There are few viable options on how to improve the situation of increasing traffic volume, accidents and delay at this intersection.

In 2004, the Hamilton County Engineer’s Office learned of a Continuous Flow Intersection (CFI) concept, which had been utilized in Mexico, and had been introduced in two areas in the United States (New York and Maryland). CFIs have since been built in several other locations and are being constructed or studied in countless other states. The concept effectively moves the left-turning traffic left of approaching vehicles before the intersection, to eliminate one or more cycles from the intersection signal. In addition, through the introduction of divider areas, it also can accommodate pedestrian traffic, even at high volume intersections. A potential application for this concept surfaced at Beechmont and Five Mile Road, on two of the “legs” (those on Five Mile), and the County approached Anderson Township about the project.

In 2004, Woolpert was hired by the County Engineer’s Office and Township to conduct a study of the potential of this concept for this intersection. The result of this study found that a two-legged CFI would improve the level of service to C (average), and cut delay times by more than half. This is important as this intersection is the key bottleneck along Beechmont Avenue (SR 125) in Anderson Township, even with a new closed loop signal system. In addition, it was determined that while some right of way acquisition was needed from several property owners and there were other driveways that needed to be moved or modified as part of the process, it would not serve as a major detriment to adjoining property owners nor hinder the use of their property.

Consequently, with this drastic reduction in congestion and resulting improvement in air quality from the 65,000 cars a day that would have their average delay cut in half or better, the Board of Anderson Township Trustees and Hamilton County Engineer’s Office believe this would be a strong utilization of Federal Congestion Mitigation and Air Quality (CMAQ) grant funds. An application was therefore submitted and approved by the Ohio-Kentucky-Indiana Regional Council of Governments for approximately $2.5 million of the projected $3.4 million project cost (80%). Several years later, Ohio Public Works Commission Local Transportation Improvement Funds were secured for the local "share" of the project's construction cost, nearly $900,000. 

Current Status of the Project

Engineering commenced in 2007 and has progressed through the normal Ohio Department of Transportation (ODOT) planning process. The design of the project was suspended for several years to facilitate important cross access connections to mitigate the project's impact on abutting property owners. These improvements were made during 2012 and 2013. Final design plans for the CFI were then prepared to bid the project in late 2015.  Construction began in the spring of 2016 and was completed by early summer 2017, as the intersection became operational in its new configuration on May 19, 2017.  Additional enhancement to the area, including landscaping, sidewalks, etc. were implemented through the fall of 2017.  

Initial Assessment of the CFI’s Operations

The CFI became operational in May 2017, and following some initial modifications in June, and following the initial six-month review period it was important to determine if the new configuration was successful in addressing the project’s goals.

These goals were: 1) Reduced vehicle delay, 2) Improved safety, and 3) Accomodation of pedestrian accessibility.  A fourth goal or priority was minimizing any impact on surrounding property owners.  This led to the CFI design as opposed to a ramp system, roundabout, dual left turn lane, or other approaches.  In fact, Anderson Township and  the Hamilton County Engineer’s Office spent years in advance of the project working to fit this in the existing, or slightly expanded, right of way, and ensure access, signage, and other needs.  Thus, project supporters believe the CFI has met that goal.

With regards to Goal 1, travel delay, Anderson Township believed  it important to seek professional guidance from an engineering consultant for such a complex analysis.  TEC Engineering was selected due to their experiences in such studies, and they were not involved with this project.  TEC reviewed the 2005 Feasibility Study conducted by Woolpert Engineers, which looked at existing travel delay and queue, and projected delay and queue with a CFI configuration and “no build” (keeping the same configuration). 

TEC’s findings indicated a reduction in delay for the intersection during the AM peak hour between the 2005 conditions and 2017, was 36.7 seconds or 57.8%.  PM figures were 44.7 seconds and 60.7% respectively.  As for queue distances, or the length of vehicle stacking, there is no overall average. However, the ranges for Beechmont (westbound and eastbound) and Five Mile (northbound and southbound) peak AM queue were down between 185 and 917 feet (39% and 78%), the largest improvement being Beechmont eastbound. The PM figures were between 80 and 1,253 feet (23% and 75%), the largest again being Beechmont eastbound.  Thus, by all accounts this goal has been more than met with the CFI configuration.  

To analyze Goal 2, Anderson Township has been following sheriff’s records since May and identified 5 accidents at this location since it opened May 19th. That equates to one every 6 weeks or so. By comparison, pre-construction of the CFI (using a 10-year average between 2006-2015), the intersection was home to about 29 accidents/year, or one every 1.8 weeks.  Though much higher than today, this was actually down considerably from the prior 10-year average (1996-2005), where this figure was nearly 44 accidents/year, or one every 1.2 weeks. 

Thus, after 6+ months, accidents are down, and the average time interval between accidents has increased by 233%.  Of course, not all accidents may have been reported the past 6+ months, but it is likely the rate of accidents “not reporting” has not changed from prior years.  A look into the accidents that were reported gives little indication that the CFI configuration was a contributing factor (cars traveling in the wrong lane, etc.).  These accidents include failure to yield when turning, rear-end collisions, and not complying with a red light. 

Further, what’s astounding is that typically when there is a traffic pattern change, (CFI or otherwise) accidents spike initially.  This has been the case with CFIs in other areas too, where there is an increase then reduction, but the initial spike in accidents has not occurred here. Finally, we understand that fortunately none of the accidents resulted in serious injuries.  Thus, the severity of the accidents that have occurred has reduced, which was a benefit of the CFI design as it reduces the possibility for angled crashes which often result in serious injuries.

Finally, with Goal 3, pedestrian access, the CFI is safely accommodating pedestrians, with crossing sequences that do not conflict with automobile traffic (i.e. left or right turn yielding on green).  Recently built and upcoming sidewalks will only make access more possible.   While it may take longer for pedestrians to cross, they formerly were only allowed to cross Five Mile (with Beechmont traffic trying to turn, too) on the north side of Beechmont and weren’t accommodated.  In fact, they were prohibited from the other three crossings.  On any given day, one may see pedestrians, runners, bicyclists, wheelchairs, strollers, etc. traversing safely from refuge island to refuge island with no impact on traffic flow.

Thus, the initial assessment of the CFI is positive, and ODOT, the Hamilton County Engineer’s Office, and Anderson Township will continue to monitor this and nearby intersections and roadways, to fine tune operations to work towards achieving the goals set forth for this project. 

Relationship of CFI to Goals of the Federal Transportation Administration's Congestion Mitigation and Air Quality (CMAQ) Program that led to the selection of this configuration for the intersection.



Goal 1: Improve Travel Safety

The CFI design concept reduces the number of turning conflicts at the intersection, and substantially reduces delay by essentially eliminating one of the four traffic signal phases. The resulting intersection is then projected to have less turning conflicts and fewer possible collisions, typically those resulting in the most severe of crashes. In addition, a reduction in vehicle delay (i.e. stopped traffic) helps to minimize potential rear end accidents with a more productive traffic flow. Finally, pedestrians are currently not permitted within the intersection, they do attempt to cross, and this is always a safety threat because there are no pedestrian signals or crosswalks. The CFI concept will accommodate pedestrian crossings with activated signals, crosswalks, and median areas elevated from traffic.

Goal 2: Improve Accessibility and Mobility Options for People and Goods

The CFI configuration will enable pedestrians to cross this intersection, which is not currently possible. This is critical as this intersection lies at the center of Anderson Township, within very close proximity to intense retail shopping (Anderson Towne Center and surrounding centers), Anderson High School, recreation opportunities (Beech Acres Park, Five Mile Trail and Anderson Lake), Anderson Center Station Park & Ride, and Anderson Center, and many residential neighborhoods. Thus, pedestrians will begin to traverse this area with safety improvements, and, facilitated by recent new sidewalk projects in this area, to connect to these destinations.

Goal 3: Protect and Enhance the Environment

As alluded to earlier, this project will achieve this goal in two ways. First, it will greatly reduce travel delays (by more than half according to preliminary studies), therefore reducing mobile source emissions. Second, it will enable pedestrians to make this new intersection crossing to travel from neighborhoods to the many attractions in this area, facilitating the greater use of walking rather than automobile use.

Goal 4: Enhance the Integration and Connectivity of the Transportation System

The CFI will enable more efficient traffic flow, for all motorized transportation. In addition, it will successfully integrate pedestrians and motorized traffic into a very dense and congested area.

Goal 5: Promote Efficient System Management and Operation

Short of building an interchange, a very costly and undesired improvement in this area, the CFI represents the best option to maximize the existing transportation network by reconfiguring lane alignments to maximize the operation of the intersection.

Goal 6: Emphasize the Preservation of the Existing Transportation System

The subject intersection already exists, and this is simply a tweak to two “legs” of the intersection that will allow it to operate at a more efficient level. In addition, this request taps Township and County funding sources to improve the operations of a key State Highway in the southeast part of the Cincinnati region.

Goal 7: Support Economic Vitality

The Five Mile and Beechmont intersection has been the center of a rebirth of Anderson Township. This is highlighted by the redevelopment of the Anderson Towne Center, but this economic investment has spread throughout the Five Mile Corridor, including three new office buildings within 1 mile that will add over 225,000 sq. ft. and hundreds of new employees to the community. This private investment, coupled with the Township's investment of over $25 Million dollars into other enhancements to Five Mile Road, a new park and ride, shared use trail, and Anderson Center in this section of the corridor, seeks to maintain and enhance the economic vitality of this region. With this, improvements to this intersection are critical to this productivity and efficiency.

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