U.S. Department of Transportation 

Federal Highway Administration 

Accommodating Trucks 

Designing Roundabouts 

for Truck Traffic 

Location 

Paola, Kansas 

Site Characteristics and 

Implementation Results 

🗸 Opened in 2002 with AADT of 

8,500 and 20% trucks. 

🗸 The first rural and high-speed 

approach roundabout in Kansas. 

🗸 Combined two closely-spaced 

intersections to form a five-leg 

roundabout. 

🗸 Reduced overall crashes by 67% 

and severe crashes by 100% 

based on a comparison of 6 years 

of before and after data. 

Strategies Employed 

🗸 Reached out to key freight 

stakeholders early in the project 

development process in order to 

obtain and incorporate feedback. 

🗸 Selected an appropriate design 

vehicle based on freight that 

travels through this intersection. 

🗸 Invested in an independent 

peer review by an expert 

roundabout designer. 

🗸 Modified curb height to help 

large trucks better traverse 

the intersection. 

🗸 Used advance transverse rumble 

strips in lieu of reverse curves to 

help raise intersection awareness 

and reduce approach speeds. 

Introduction 

Maneuvering through intersections can be challenging for trucks, and these challenges 

become even more pronounced when the load is exceptionally large or heavy. Oversize/ 

overweight (OSOW) vehicles are particularly sensitive to how intersections are designed. 

The geometry of roundabouts must be carefully considered to achieve a good balance 

between safety for all users and the basic ability 

of freight to flow through the intersection. 

Working together, road agencies, freight 

company owners, and truck operators can 

improve both the design of roundabouts and 

the ability of drivers to navigate them. 

Background 

With over 140,000 miles of public roads, Kansas has the third-most public road miles of 

any State, although its population ranks only 33rd. More than 90 percent of those miles 

are considered rural, and a substantial portion of the vehicle-miles traveled involves 

commercial motor carriers on rural highways carrying long-distance freight loads or 

goods related to the State’s extensive agriculture industry. As a result, the safe and 

efficient movement of trucks on rural highways is vital to the Kansas economy. 

Additionally, recent trends in the renewable energy industry have increased the volume of 

OSOW vehicles on Kansas roadways. For example, transporting a blade for wind turbines 

requires an OSOW vehicle with trailers as long as 80 feet without rear-wheel steering. 

In 1996 , the Kansas Department of Transportation (KDOT) identified the intersections 

of Kansas Highway 68 (K 68) with Old Kansas City Road and Hedge Lane near Paola as a 

high-crash location. The location featured two closely-spaced intersections: Old Kansas 

City Road and K-68 was a four-leg, two-way stop-controlled intersection; Hedge Lane 

terminated at a T-intersection with K-68 approximately 200 feet away. All were two-lane 

roads. The posted speed limits were 65 mph along K-68 and 55 mph on Old Kansas 

City Road. The combined average annual daily traffic (AADT) at the intersections was 

approximately 8,500, 20 percent of which were large trucks. 

In 1998, KDOT temporarily changed the Old Kansas City Road intersection to all-way 

stop control with larger signs and a flashing beacon, but right-angle and high-severity 

crashes continued. Rather than install a traffic signal, KDOT evaluated other solutions 

with the potential to reduce crashes 

and accommodate future traffic 

volume growth, and determined that 

a roundabout was the best solution. 

Given the high volume of truck traffic 

using the intersection, KDOT carried out 

targeted outreach efforts to understand 

the needs of area freight stakeholders 

and adjust the roundabout design to 

accommodate their operations. Figure 1 & 2: K-68 Before and After 

Source: Google Earth Pro FHWA-SA-14-013 

Revised June 2020

Safe and efficient movement 

of trucks on rural highways is 

vital to the Kansas economy. 
Based on freight stakeholder input, KDOT 

reduced truck apron curb heights at the 

roundabout to provide a more forgiving 

edge of traveled way for large trucks. 

Lessons Learned 

Roundabouts can provide substantial 

safety improvements at rural, high-speed 

approach intersections. 

Proactive outreach to freight-specific 

businesses gets them involved in the 

design process, resulting in roundabout 

features that can work better for trucks. 

Other Resources 

KDOT QuickFacts 

http://www.ksdot.org/PDF_Files/ 

QuickFacts2010.pdf 

Kansas Roundabout Guide 

http://www.ksdot.org/Assets/ 

wwwksdotorg/bureaus/burTrafficEng/ 

Roundabouts/Roundabout_Guide/ 

KansasRoundaboutGuideSecondEdition.pdf 

Roundabouts in Kansas Video 

http://www.youtube.com/ 

watch?v=HnIxJ2CTBXk 

Figure 3: Truck navigating a roundabout 

Source: KDOT 

Learn More 

Brian Gower 

State Traffic Engineer 

Kansas Department of Transportation 

7 8 5 . 2 9 6 . 3 6 1 8 

gower@ksdot.org 

Jeffrey Shaw 

Intersections Program Manager 

FHWA Office of Safety 

2 0 2 . 7 3 8 . 7 7 9 3 

jeffrey.shaw@dot.gov 

Approach 

The Paola area is home to a number of freight-related businesses, including a major 

warehouse distribution center and a commercial vehicle driving school. KDOT knew 

the new roundabout needed to accommodate large vehicles. They also understood 

the importance of the roundabout providing both safety and operational benefits 

compared to other intersection designs. KDOT undertook several stakeholder 

involvement activities prior to and during the design process in order to deliver a 

project that would meet agency safety goals and serve the freight community. 

For most projects on state highways, KDOT evaluates a combination semi-tractor and 

53-foot trailer (an AASHTO WB-67) as the design vehicle, while also considering possible

OSOW loads that might travel through the intersection . With the Paola roundabout

located east of a Walmart distribution center, KDOT knew there would be a high

volume of truck traffic using the intersection. Accordingly, their first key decision was

to continue their practice of using a WB-67 semi-trailer as the design vehicle for the

roundabout. This assisted with the alignment design of the approaches and circulating

roadway to provide sufficient accommodation for freight traffic and emergency

vehicles to safely and efficiently navigate through the intersection.

With a draft design completed in-house, KDOT hired an external roundabout design 

expert to conduct a peer review of the roundabout’s ability to accommodate trucks 

and achieve the desired safety improvement. KDOT used the resulting design when 

meeting with freight stakeholders, many of whom had expressed initial opposition 

to the roundabout idea. KDOT contacted representatives from the freight industry to 

present the roundabout design, discuss the other intersection options considered, and 

solicit feedback. This allowed KDOT to present their concept and justification for the 

roundabout while also being responsive to stakeholder concerns. 

Results 

As a result of the outreach efforts to freight stakeholders, KDOT reduced curb heights 

on the truck aprons at the roundabout to provide a more forgiving edge of traveled 

way to large trucks. Additionally, KDOT had planned to use reverse curves on the 

approaches to the roundabout to help reduce speeds into the intersection. However, 

to alleviate the concerns expressed by the stakeholders, KDOT agreed to use elongated 

splitter islands with advance transverse rumble strips instead. 

KDOT proceeded to construct the roundabout and opened it to traffic in 2002. It was 

a “first” roundabout for Kansas in two ways: the first with high-speed approaches and 

the first in a truly rural setting. Additionally, the roundabout featured five legs, due 

to combining the two original intersections – one four-leg and one three-leg - into a 

single intersection that preserved the 55 mph and 65 mph posted speed limits on the 

approaches. Data shows a marked reduction in crashes after construction. From 1995-

2000, there were 33 crashes with 42 injuries in the six years prior to the roundabout 

installation. After the roundabout was installed, these numbers declined dramatically 

with 11 crashes and zero injuries in the six years following installation (2003-2008). 

Despite some initial trepidation, the roundabout has exceeded the expectations of the 

agency and the public for improving safety and accommodating freight movement. 

The success of this installation has led KDOT to install five more roundabouts at rural, 

high-speed approach intersections on the State highway system, and two more are 

planned for construction. In addition, KDOT used the knowledge and experience 

gained from this project to create the Kansas Roundabout Guide to assist local Kansas 

agencies in assessing the viability of roundabouts in their areas. The second edition of 

the guide was published in spring 2014.