Earlier this year, Georgia DOT held a virtual open house to show plans for dual roundabouts in McDonough. Now, the state has replied to comments received during the open house.
The project plans to construct dual roundabouts off state route 20. Specifically, the location includes Lawrenceville Street and McGarity Road. Fairview Drive is also inside the project footprint.
State Route 20 Dual Roundabouts
Design for the project began in 2018. Alternatives considered were the following:
- Construct two single-lane roundabouts
- Signalize the two intersections
- Re-align Lawrenceville Street to form a T-intersection with state route 20
Modeling shows the two single-lane roundabouts will reduce traffic delays more than the other alternatives. The model forecasts intersection delays in twenty yearsâ€™ time (year 2043). The roundabouts would reduce AM peak hour delays by an estimated 89% and PM peak hour delays by 86%. Comparatively, the two signals will reduce delays by -1% (AM) and 26% (PM). For this reason, the state DOT selected two roundabouts as the preferred alternative.
Right of way acquisition started in fall 2020. Construction is presently on schedule to begin during fall 2022.
Georgia DOT response
Georgia DOT received sixty comments during the project open house. Of those who replied, 31 were in support of the project. In addition, 21 were opposed, 4 were uncommitted and 4 expressed conditional support.
Below includes excerpts from the state DOT response:
Multiple comments regarding the roundaboutâ€™s ability to accommodate tractor trailer traffic.
Response: The roundabout design and width accommodates the turning movements of large trucks, buses and tractor trailers. It has a mountable truck apron for the path of the supporting trailer.
How will drivers make a left turn in between the roundabouts? Specifically, at Fairview Drive. The roundabouts are too close together.
Response: Roundabouts operate in a counterclockwise movement to only permit right turns. Drivers will not be able to make a left turn in between the roundabouts due to the raised concrete median. A left turn movement will not be possible from Fairview Drive onto State Route 20.
Multiple comments regarding the selection of the roundabout as the preferred alternative (instead of traffic signals) since roundabouts are allegedly not safe for pedestrians.
Response: The decision to propose a roundabout as the preferred alternative is validated through the Intersection Control Evaluation (ICE) Stage 1 – Screening and ICE Stage 2 – Alternative Selection. The ICE Stage 1 and 2 was completed for both intersections where a roundabout is proposed. These studies evaluate the performance of many types of intersection and interchange controls for locations and seek to determine the best possible overall value in terms of performance-based criteria.
Roundabouts demonstrate several safety and operational benefits over traditional stop-controlled intersections. Traffic signals do not eliminate crossing movements nor force drivers to slow down through the intersection, leaving the potential for high speed, angle crashes. By contrast, a roundabout eliminates vehicular crossing paths, restricts speeds of traffic, and allows drivers to focus their attention on circulating traffic approaching from one direction (the left).
Furthermore, the consequence of errors at roundabouts is less severe than at conventional intersections, due to lower speeds. Roundabouts also create fewer delays than traffic signals due to the reduced number of vehicles required to stop, and typically operate with lower vehicle delays than other types of intersections and controls. As a result, roundabouts are viable solutions for both peak and non-peak hours.
Studies show that a signal can reduce delays to an acceptable level, but also result in an increase in the number of crashes. These studies also show that a roundabout can provide much greater reductions in delay, and a safer intersection. In many cases, a roundabout can offer a safer environment for pedestrians than a traffic signal. The pedestrian crossing at a roundabout consists of two simple crossings of one-way traffic moving at slow speeds. A pedestrian crossing at a traffic signal still needs to contend with vehicles turning right or left on green, vehicles turning right on red, and vehicles running the red light. The latter of these potential conflicts occur at high speeds and often result in injuries or fatalities to pedestrians.
Multiple comments that the project will cause more traffic delays and congestion because of increased traffic.
Response: Roundabouts, by their nature, allow for a steadier traffic stream (as opposed to signals or all-way stops) and will allow for a more efficient traffic operation while still reducing the potential of crashes.
Featured image shows project concept layout for state route 20 dual roundabouts. Photo credit Georgia DOT.
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