GDOT Proposes Exit Ramp For Windward Parkway Express Lanes

ALPHARETTA, Ga. — As part of its proposed Ga .400 Express Lanes Project, the Georgia Department of Transportation is proposing creating a new dedicated exit ramp. The ramp would be for the express lanes in the area between the existing Webb Bridge Road overpass and the Windward Parkway exit. Referred to as Webb Plus, the proposed dedicated exit would provide connection to Westside Parkway and North Point Parkway for drivers using the new express lanes.

Five things to know, from the City of Alpharetta:

1. The express lanes will feature “dynamic pricing,” rising as demand increases during peak travel times and falling at off-peak times, giving drivers the choice to pay a fee to bypass congestion.
2. GDOT expects that new express lanes will provide more reliable trips along the Ga. 400 Corridor.
3. Georgia’s first bus rapid transit (BRT) system is planned to run along this project corridor. Once completed by MARTA, transit providers will have access to the express lanes at multiple access points along the corridor.
4. Transit riders and registered van pools can use the lanes without paying any additional fees.
5. This is one of GDOT’s initial 11 large-scale Major Mobility Investment Program projects they are undertaking to improve transportation in Georgia’s metro areas.

The following is an animation of the proposed Ga. 400 Express Lanes Project as currently envisioned. While this video provided by GDOT offers an overview of the project vision, it may not be representative of the final design of the project:

Once drivers reach the area of the Webb Plus interchange, the model is estimating that the new overpass over Ga. 400 and Express Lane access point would likely change vehicle routes. Other estimates from GDOT show that most driver routes beginning or ending outside of the area between North Point Parkway and Westside Parkway will remain unchanged as these routes will still be the most convenient way to reach this area, either for a local trip or for accessing Ga. 400

Questions were raised during a previous public comment, including, "Westside Parkway reflecting a 25 percent or more increase in traffic. Additionally, the study reflects that the eastside of Windward Parkway and North Point Parkway will have a zero - 10 percent increase for the eastern most section of Windward up to North Point Parkway. It then reflects a zero or less percent increase when it crosses North Point Parkway to the Ga. 400 Interchange and it also reflects zero or less percent increase from North Point Parkway to the Webb + interchange."

Senior Traffic Engineer for AECOM, which completed the study, Jeff Wood said there are a few reasons the Travel Demand Model (or TDM) is showing these results.

"First, I would expect that the major East-West routes, such as Windward Parkway and Ga. 120/Old Milton Parkway won’t be affected very much east of North Point Parkway and west of Westside Parkway," Wood said. "The TDM is estimating in the Trip Assignment stage that for most drivers these routes will still be the most convenient way to reach this area (either for a local trip or for accessing Ga. 400) meaning most people’s routes are unchanged outside of the area between North Point Parkway and Westside Parkway. Once drivers reach the area in the vicinity of the Webb Plus interchange this is where the model is estimating that the new overpass over Ga. 400 and Express Lane access point would likely change vehicle routes."

Wood went on to say that within this area, the TDM trip assignment is finding the new overpass and Express Lane interchange is attractive for people making trips from the southeast of Webb+ or from the northwest of the Webb+ interchange.

"More specifically what appears to be happening is that two types of local trips have been diverted from their normal path and some of the ramp traffic at Windward Parkway and Ga. 120/Old Milton Parkway have diverted from their normal path," Wood said.

The two local trip paths that were diverted across the new Webb Plus interchange are shown in the two maps here.

To learn more about the Webb Plus Proposal and the Ga. 400 Express Lanes Project, visit https://bit.ly/2T8Xagz. Select the “Documents” tile near the bottom of the page to access more detailed information, including traffic modeling data on how the Webb Plus Proposal may impact local roads.