Speaking

The Diverging Diamond Interchange (DDI) is emerging as a cost-effective interchange configuration that solves congestion and safety issues. Owners are continuing to consider implementing these increasingly popular solutions. However, owners often lack the expertise required to oversee DDI design and construction. This presentation will discuss some lessons learned during the planning, design, and construction of DDIs across the country, and introduce strategies for overcoming DDI-specific challenges.

This presentation will directly address well-known DDI challenges such as the concern that DDIs violate driver expectations, or that DDIs don’t work with closely-spaced adjacent signalized intersections. It will also address some of the myths surrounding DDIs, including one that DDIs are not pedestrian or bicycle friendly.

Other key discussion points in this presentation include:

• The importance of a well-defined eye brow
• Good geometric strategies for the ramps and the crossover intersections
• Optimal signal head placement to maximize sight distance
• Signing strategies, maintenance of traffic and construction strategies
• Public involvement strategies

This presentation will show DDI best practices as well as areas for further improvement with several examples of both good and bad strategies that have been implemented. The audience will learn what a cost-effective DDI that maximizes safety for all users looks like and how to promote these innovative interchanges to the public.

Roundabouts have become almost common place in certain pockets of the country as a means of providing a safety improvement at a problematic intersection. However, many regions still don’t have the desire or the understanding of what it takes to construct a roundabout. Often, public opinion tends to lead the recommended solution away from the roundabout based on myths or perceived fears. This presentation will discuss some lessons learned during the planning, design, and construction of roundabouts across the country, and introduce strategies for overcoming roundabout-specific challenges.

This presentation will give a brief overview as to the benefits of roundabouts, and directly address well-known challenges such as the concern that roundabouts are challenging to drive or that roundabouts aren’t safe. Other key discussion points in this presentation include:

• Keys to good roundabout geometrics, including entry alignment, entry and exit widths and curves, and path overlap in the roundabout
• Accommodating acceptable speed profiles and phi angles
• Speed-reducing geometry approaching the roundabout
• Signing strategies
• Accommodating various design vehicles
• Placement of pedestrian and bicycle facilities through the roundabout
  

This presentation will show roundabout best practices as well as areas for further improvement with several examples of both good and bad strategies that have been implemented. One topic that will be discussed is the “double double” issue that occurs with multi-lane roundabouts. Attendees will learn what a roundabout that maximizes safety for all users looks like. They also will learn how to promote these intersection improvements to the public.

Tremont Road, a major urban collector in Upper Arlington, Ohio, connects residents to the main branch of the city library, an elementary school, a park, and many businesses. With failing infrastructure in need of major repairs, Burgess & Niple worked with the City of Upper Arlington to go beyond a simple two-mile reconstruction project to create an inviting, multi-modal corridor using Upper Arlington’s new Complete Streets Policy.

The B&N team enhanced bicycle and pedestrian facilities, coordinated with local transit stops, addressed intersection geometric and midblock crossing concerns, and provided cohesive aesthetic elements while minimizing right-of-way impacts.

A road diet repurposed the available room within the existing right-of-way in part of the corridor, creating space for bike lanes, tree lawns, and wider sidewalks. New shared-use paths and sharrows tied into the bike lanes, provide links for future bike connections. Two intersections with confusing geometry were simplified to a standard intersection and a mini-roundabout, provided clear paths for all users while remaining within the existing right-of-way.

The team eased the concerns of the Upper Arlington fire chief with a firetruck ride-a-long through several existing roundabouts and a final test run with a pumper truck thru the new mini roundabout. Key mid-block crossings were enhanced with medians or rapid rectangular flashing beacons for pedestrian visibility and safety. Public outreach shared the project and gathered input on intersection alternatives, bike facility types, and aesthetic choices.                

Additional outreach held prior to construction to discuss maintenance of traffic phasing, temporary access concerns, and construction schedule.