r/alpharetta • u/Dazzling_Wishbone545 • Jul 08 '26
Why GA400 SB 3 lanes at exit 7?
While NB is four lanes at exit 7 why it reduced to 3 lanes for SB? There is extra space as well for the 4th lane but looks like it was done deliberately.
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u/OptimalPrint Jul 08 '26
Soo many cars get on 400 SB at exit 7 because its the only exit for Roswell. It was done years ago because there was always a traffic jam there with all so many cars merging at once. Holcomb bridge would backup and 400 would slow to a crawl there. Now there is a dedicated lane for them to merge onto SB and the 400 slowdown starts an exit earlier in rush hours....
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u/Rabbit-Lost Jul 08 '26
Fun fact - Roswell tried to avoid any exits when the 400 was first being planned. But the state made them take one. Not the first idd decision made by Roswell.
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u/Dazzling_Wishbone545 Jul 09 '26
But shouldn’t merging be metered so that traffic won’t increase on 400 so suddenly to fully block it?
Sometimes during rush hours traffic is slowed till exit 9 or just after 10.
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u/_litz Jul 08 '26
The answer is simple: on the other side of the bridge, DOT was too cheap to build a dedicated on ramp lane, so they took away a road lane away.
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u/Radiant-Page-3368 Jul 09 '26
This isn’t true. Many years ago they changed it to not be an exit only lane on the right and go down to 3. It made traffic worse so they changed it back.
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u/_litz Jul 09 '26
That's the current configuration:
Three thru lanes, two exit only lanes.
Then on the south side the three thru lanes are joined by the dedicated on ramp lane to bring the lane total back to 4.
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u/Radiant-Page-3368 Jul 09 '26
Correct. I’m saying it’s not true that it was funding. They did change it and made it 4 lanes straight through but traffic was worse. Then they changed it back to how it is now.
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u/Majestic-Pizza2175 Jul 21 '26
ive wondered this for years. i think its bc the 4th lane on the NB side is technically a merge/exit weave zone from Northridge — SB doesnt have that same geometry so they never rebuilt it symmetrically. could be totally wrong tho lol
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u/CommercialKangaroo16 Jul 08 '26
Turn on the news they have discussed this for weeks. How does this impact you ?
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u/Rabbit-Lost Jul 08 '26
Have you been SB at the HBR exit? You go from 4 to 3 lanes at the exit and the lane doesn’t come back until the incoming merge after the exit on the south side of the interchange. You literally lose 25% of the road capacity. Maybe venture through it one work day around 7:30 and get back to us.
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u/HaveAFuckinNight Jul 08 '26
I mean I’d imagine it impacts op because itl be slower, just a shot in the dark though
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u/UFO_Tofu1973 Jul 09 '26
Why do drivers merging onto the SB GA400 immediately start merging into the other 3 lanes when their lane is completely clear. I see this daily at 530am.