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Road Mobility & Reliability

Mobility & Reliability is Key to Business Sucess

The OKI region’s quality of life and economic competitiveness are closely related to the degree to which the road network can provide an acceptable level of mobility. Other modes such as rail, river, air, or pipeline may be involved in various legs of a cargo’s journey. However, trucks remain the dominant freight mode for making first- and last-mile deliveries. On-time, reliable delivery is critical to business success, not only to keep customers satisfied, but to minimize labor, fuel and other expenses — which can make or break a company’s bottom line.

Truck Vehicle Miles Traveled

In 2019, trucks traveled 5.2 million miles on our region’s roadways. This sounds like a huge number; however, the translation is that trucks comprise only 9.8 percent of all the vehicle miles traveled (VMT) in this one year. The OKI region is on par with the nation in terms of VMT. Nationally, trucks comprise 9.4 percent of all vehicle miles traveled.

Hamilton County handles about 40 percent of both the region’s total VMT and truck VMT. The same is true in Warren County, though at lower VMT levels (about 12 percent). However, truck VMT within both counties is only 9.7 percent of their total VMT. In contrast, Boone, Dearborn, and Kenton roadways carry higher percentages of truck VMT on their roadways, at 17 percent, 14 percent and 13 percent, respectively.

Trucks comprise only 9.8% of the vehicle miles traveled on our region’s roadways by all motor vehicles.

Truck Volume

Truck volume is reported by Truck Average Annual Daily Traffic (TAADT). TAADT represents the typical number of trucks traveling on any given day. It is calculated by taking the percentage of trucks and multiplying it by the AADT of all vehicles.

Truck volumes have increased across the OKI region over the past decade. A sampling of interstate locations provides a snapshot of the tremendous growth in truck traffic. Between 2009 and 2018, truck volumes on I-75 have increased from 122 percent in Butler County to 165 percent in Warren County. The I-75 corridor is a major north-south transportation artery, and one of the busiest freight routes for trucks in the region. As such, it is an important link for the local, regional and national economies. Serving as the OKI region’s linchpin in the I-75 corridor is the Brent Spence Bridge (BSB). Opened in 1963 to carry 80,000 vehicles a day, including 3,000 to 4,000 trucks, the bridge currently handles about 160,000 vehicles daily — about 19 percent, or 30,000, of which are trucks.

Truck counts for Interstate 71 (I-71) in Hamilton County increased 185 percent between 2009 and 2018. I-71 is 346 miles long and connects the OKI region south to Louisville, Kentucky, and north through Columbus to Cleveland, Ohio. Several 2018 traffic counts along I-71 in the OKI region reported truck volumes comprising 25 percent or more of all vehicles traveling the corridor.

Interstate 74 (I-74) is 419 miles long and connects the OKI region through Indianapolis to Davenport, Iowa. Truck volumes of more than 30 percent have been reported in the I-74 corridor.

Interstate 275 (I-275) encircles a large portion of the OKI region in southwest Ohio, a small segment in Dearborn County, Indiana, and the northern sections of Boone, Kenton, and Campbell counties in Kentucky. The entire I-275 loop is 83.7 miles long. Segments of I-275 in Ohio, east of I-71, report truck volumes of more than 30 percent of the total traffic. Due to the nature of I-275 as a beltway around the OKI region, it is not surprising that TAADT can vary. Case in point, an I-275 location in Clermont County had a 94 percent increase between 2009 and 2018, while one in Kenton County rose more than 273 percent.

Interstate 471 (I-471) is a 5.75-mile-long highway in Campbell County. It links I-71 in downtown Cincinnati to I-275 in Highland Heights, Kentucky. I-471 south of I-275 turns into US 27. TAADT on I-471 has seen a rise in truck traffic of more than 416 percent between 2009 and 2018.

View the most current truck crash data within OKI’s Interactive Truck Map


There are two types of congestion. First, recurring congestion is caused by consistently excessive travel demand, as compared to available roadway capacity. Contributors to recurring congestion are inadequate engineering or design elements. These can include, poor signal timings, uncontrolled accessibility off/on the roadway, or geometric deficiencies. Nationally, these types of inferior physical conditions cause about 45 percent of all congestion.

Comprising the other 55 percent of all congestion nationwide is non-recurring congestion. Non-recurring congestion arises from involuntary, temporary, and emergency events, such as traffic incidents (25 percent); adverse weather (15 percent); road construction work zones (10 percent); and special events (5 percent).

Truck Travel Time Reliability

OKI uses a measure called the Level of Truck Travel Time Reliability (LOTTTR) to weigh the performance of the roadway freight system and help identify locations where congestion is most severely impacting trucks. LOTTTR measures the consistency of truck travel times or the degree to which delays are unexpected. The LOTTTR is a ratio calculated by dividing the 95th Percentile Travel Time by the 50th Percentile Travel Time. LOTTTR is calculated by peak travel times of the day for only the interstate system. All freight roadway segments, or Traffic Message Channels (TMCs), have an LOTTTR target of less than 1.5. The lower the ratio, the more reliable the travel speed and, therefore, truck travel time. Interstate segments that have a reliability index of 1.5 or greater during any time are considered to be unreliable.

OKI used a weighted average by distance in miles for all interstate segments for each county to attain an LOTTTR index by time period. This analysis shows that interstate segments in Kenton County have the highest LOTTTR, 2.12, during the PM peak travel time, which means truck travel time during 4 p.m. to 8 p.m. is unreliable. Hamilton County’s PM peak LOTTTR is 1.63 which makes truck travel time also unreliable. Kenton is the only county in the region with an LOTTTR above 1.5 for the Midday Peak and Weekend travel times.

To view the most current truck travel time data visit OKI’s Interactive Truck Map

View the most current truck travel time within OKI’s Interactive Truck Map

Truck Bottlenecks

To identify the region’s top truck bottlenecks or worst interstate locations for travel time reliability, OKI used National Performance Management Research Data Sets (NPMRDS) to identify road segments called Traffic Message Channels (TMCs) with the highest AM and PM peak period LOTTTR indices for the 2021 calendar year. Those TMCs that reported the highest LOTTTR and were contiguous were grouped together to form a single corridor. OKI conducted this process for both AM Peak and PM Peak LOTTTR values, until five unique corridors with the highest LOTTTR values for each peak period were identified.

The highest 16 TMC LOTTTR values form the top five truck bottlenecks for AM peak travel. The Brent Spence Bridge Corridor in Cincinnati from Western Avenue/Liberty Street southbound to the bridge reported the highest, most unreliable 2021 AM peak truck travel time in the OKI region. Seven contiguous segments were joined to create this 1.29-mile-long bottleneck corridor. The second AM Peak truck bottleneck corridor is also related to the Brent Spence Bridge. The northbound approach to the bridge from Dixie Highway in Fort Mitchell to Covington’s Pike Street exit has the second highest, most unreliable 2021 AM peak truck travel time in the region.

The highest 17 TMC LOTTTR values form the top five truck bottleneck corridors for PM peak travel. Examining the top 5 truck bottleneck corridors for the 2021 PM peak travel time, once again the Brent Spence Bridge Corridor is high on the list. For the PM peak, the northbound I-75 segment in Fort Mitchell tops the list while the southbound BSB corridor in Cincinnati is third. The almost one-mile, northbound I-75 segment in Kenton County has the highest of all 2021 LOTTTR AM or PM peak values of 8.87 at TMC ID#122P04475. The PM Cincinnati BSB bottleneck extends a half mile farther north than its AM bottleneck. The second worst PM peak truck bottleneck is the I-71 southbound approach into downtown Cincinnati. This 1.30-mile corridor starting at the I-71 Montgomery Road exit in the Evanston neighborhood of Cincinnati reported a very high 2021 LOTTTR.

National Ranking of OKI Truck Bottlenecks

Since 2002, the American Trucking Research Institute (ATRI) has published an annual ranking of the nation’s worst locations for truck delay (ATRI did not publish the rankings in 2012 and 2016). Having access to an extensive truck GPS database, ATRI uses a different process than OKI to identify the country’s top 100 truck bottlenecks. Although a different methodology is used, there are similarities between ATRI and OKI’s examination of truck bottlenecks. Foremost: Both lists include the Brent Spence Bridge.

Brent Spence Bridge Delay

The Brent Spence Bridge (BSB) has not just appeared in ATRI’s Top 100 Truck Bottlenecks List, but it has been in the top 10 for the past decade, alongside those located in much larger cities, such as New York, Houston, Atlanta, Chicago, and Los Angeles. ATRI’s past two publications list the BSB as the second worst truck bottleneck in the country. This ranking is based on findings that show the average speed during AM and PM peak travel times as only 33.6 miles per hour (mph). Nonpeak average speeds only improve slightly to 40.6 mph. This section of I-71/75 has a 55 mph posted speed. Conditions are not improving for trucks using the BSB. ATRI reports that peak average speed in 2021 decreased 16.3 percent compared with 2020 mobility data.

For more than two decades, a project to improve the BSB has been under discussion. Its goals would be to improve traffic flow and travel times (reduce congestion/improve travel time reliability); improve safety; correct geometric deficiencies; and maintain connections to key regional and national transportation corridors. In December 2017, the Kentucky Transportation Cabinet released the Brent Spence Strategic Corridor Study. It looked at a variety of options to relieve congestion and improve north-south mobility in the OKI region. The study confirmed that the BSB replacement/rehabilitation project is needed. (Source: Wray, Jerry. Ohio Department of Transportation (ODOT). Revised FHWA Re-Evaluation of Brent Spence Bridge Replacement/Rehabilitation Project. (2018).)

In 2021, as part of the Ohio Department of Transportation’s update to its state freight plan, Transport Ohio, the BSB was studied to document its importance to freight. From Nov. 11 through Dec. 22, 2020, the BSB was closed to all traffic due to a severe truck crash and explosion, which damaged a section of the structure. During the 41-day closure, traffic was rerouted. ODOT studied the before, during and after truck traffic patterns. Based on ODOT’s calculations, 13,252 trucks per day were impacted during the closure; truck trips increased by about 13 minutes; and the median trip distance increased by about 17.6 miles. (Source: Ohio Department of Transportation (ODOT). Transport Ohio, Existing Freight System Performance, Working Paper 5. (2021).)

I-275 Interchange in Kenton County

The I-71/75 interchange with Interstate 275 (I-275) in Kenton County has also appeared in ATRI’s Top 100 Truck Bottlenecks List for more than a decade. The I-275 Interchange’s bottleneck position has gradually worsened from the 108th to 24th in 2021. OKI’s analysis supports ATRI’s findings, as the eastbound section of I-275 in Kenton County — from the interchange to the Turkeyfoot Road (Exit 81) — reported the fourth worst 2021 TTTR for the AM peak at 5.46 (TMC ID#122N04512). Fortunately, ATRI’s 2022 list showed an improvement in the interchange’s peak average speed by six percent, which moved it from 24th to 71st position nationally. This improvement is based on ATRI’s findings that the average speed during AM and PM peak travel times is 48.0 mph. With nonpeak average speeds improving slightly to 52.8 mph. The posted speed is 65 mph for all 24 miles of I-275 in Kentucky.

I-75/I-74 Interchange in Hamilton County

The third and final truck bottleneck that has also been included in ATRI’s Top 100 list for more than a decade is the 1-75/I-74 Interchange -- which connects Cincinnati with Indianapolis. In contrast to the BSB and the I-275 Interchange in Northern Kentucky, the I-75/I-74 Interchange has witnessed a steady improvement in its average speeds. Therefore, its ATRI ranking as gone from the 26th worst truck bottleneck in the country in 2012 to 96th in 2021. In 2021, its AM and PM peak average speed was 46.4 mph and nonpeak average speed was 52.4 mph. The posted speed for both I-75 and I-74 in this area is 55 mph. Although, the interchange barely made ATRI’s Top 100 List in its last publication, its peak average speed percent change between 2020 and 2021 worsened by 4.6 percent.

Impact of Rail Crossings on Trucks

In 2020, the Ohio Rail Development Commission (ORDC) and their consultant team conducted an Ohio Rail Crossing Pilot Study. The study’s objective was to develop, apply and validate a methodology to evaluate the relative impact of occupied public rail grade crossings on motorized road users. This included trucks and non-motorized users, such as bicyclists and pedestrians. The study used several datasets related to public importance, delay to road users, redundancy, and safety. The study’s result: The creation of an “Adaptive Capacity Score”, or ACS, which helps provide an empirical basis to identify crossings for potential improvement.

OKI staff applied ORDC’s ACS methodology to create an ACS tool for the public rail grade crossings in the eight-county region. For various criteria, each public rail grade crossing receives an ACS point value ranging from zero to five. The higher the ACS value, the greater the impact to users of the public roadway. The results of OKI’s application of the ACS tool are discussed in detail within the Existing Rail Freight System Performance Summary. In the discussion that follows, only the information related to the impact of rail grade crossings on trucks that was obtained through the ACS tool is presented.

Overall Truck ACS

Regarding road freight, several criteria used in the ACS tool relates to trucks. There is an overall truck ACS value that determines the combined impact of four factors:

  • Delay to road users – the expected magnitude of delay to trucks due to occupancy of the crossing by a train.
  • Redundancy – proximity to other locations where trucks can cross the tracks unimpeded.
  • Public importance – how important a crossing is for trucks based on how much traffic uses the crossing and the types of land use on either side of the grade crossing.
  • Safety – a ranking of hazard risk at the crossing.

By examining the Truck ACS value, we find that Butler County is home to the three, least-safe, least-redundant, highest-delay, and highest publicly important crossings for trucks in the OKI region. In fact, Butler and Hamilton counties encompass the entire top 10 list of crossings for this composite score. Norfolk Southern is the railroad operator for eight of the top 10 Truck ACS crossings.

Truck Delay ACS

The truck delay ACS calculation uses data such as the crossing’s average number of trains per day; distance to the closest rail siding or yard; the posted maximum train speed; and the road’s average daily truck traffic count. Upon closer examination of those crossings that reported the highest ACS values for truck delay, once again, Butler County and its SR 127 tops the list. By isolating this one factor — truck delay — the crossings most impacted are located more widely throughout the OKI region, than the overall Truck ACS, in all but three counties.

Redundancy ACS

The truck redundancy ACS calculation uses data such as the crossing’s proximity to the nearest grade separated crossing (overpass or underpass) and the road’s average daily truck traffic count. Upon closer examination of those crossings that reported to be the least redundant meaning they are far from other locations where trucks can cross the tracks unimpeded, Butler County has the top five crossings with SR 127 in the second seat.

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