Read something online recently about roads that have a different speed limit for each direction of the road. Not from construction or there being more/less lanes, but just a different limit for each side. What are some examples of this and what is the reasoning?
I-94 in Dearborn. 70 MPH WB/55 MPH EB the reason, the Ford Freeway was built to a 55 MPH standard starting in the late 40s, whereas the WB section is interstate standard for 70 MPH.
I don't know whether it's still the case, but in the summer of 1997, I-65 just north of the Alabama River near Montgomery had a 70-mph speed limit northbound and a 60-mph speed limit southbound for traffic approaching the city. I guess I could look at Street View, but I'm not motivated to do so.
I don't know whether this one counts: On I-95 in Virginia, the reversible HO/T center carriageway generally has a higher speed limit than the general-purpose lanes to either side of it (for the most part, it's posted at 65 mph while the general-purpose lanes are posted at 55 or 60, and there's a segment further south where the HO/T lanes are posted at 70 while the general-purpose lanes are posted at 65).
There are multiple instances of 55 mph zones on I-79 south of Washington, PA on only one side, the other side was still 70
These examples are actively being reviewed for a change to get the discrepancy fixed.
SR-20 east of Hawthorne has a short section signed 45 EB (https://maps.app.goo.gl/LkPCGe2V6szrNFBd6) and 50 WB (first 50 sign: https://maps.app.goo.gl/jvLYHvYLHpDLagwP7 || where the EB 45 zone effectively ends: https://maps.app.goo.gl/ZigHmzPnZhp1ae6k7).
Much of SR-230 is signed as 60 WB and 55 EB, though it technically is only 55 in Bradford county. EB 55 sign: https://maps.app.goo.gl/ahPV8oBY2QZWJDWW7 || EB 60 sign: https://maps.app.goo.gl/86uKvvTkCuUAVMZAA || WB 60 sign: https://maps.app.goo.gl/K24MCWyzVnCbqos46
Frontier Parkway on the Prosper-Celina line in North Texas is signed 45 mph eastbound but drops to 30 mph westbound starting a quarter-mile back of the traffic signal at Preston Road. I'm guessing reason being because of backups at the signal.
There was a time where I used to live where a 2-lane county road was 35 MPH SB and 45 MPH NB... The former was technically within the city limits, while the latter was in the adjoining township.
NY 27 in western Nassau, near the Queens border has two different speed limits. Westbound is 45 mph and eastbound is 40. This is because the westbound lanes run parallel to the LIRR tracks, so there are few parking lots/driveways on that side. The eastbound side has many parking lots and intersections.
I-95 in Houlton, ME, approaching Canada customs northbound, drops to 65 MPH (https://www.google.com/maps/@46.1420506,-67.8272407,3a,90y,73.85h,74.18t/data=!3m8!1e1!3m6!1sIJns9MyBGXZrwdBbtXyOuw!2e0!5s20220801T000000!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D15.822251933771469%26panoid%3DIJns9MyBGXZrwdBbtXyOuw%26yaw%3D73.85255770513164!7i16384!8i8192?entry=ttu&g_ep=EgoyMDI1MDgxMi4wIKXMDSoASAFQAw%3D%3D) from 75 MPH after the Exit 302 on-ramp, and then again to 40 MPH (https://www.google.com/maps/@46.1336827,-67.7945886,3a,75y,118.85h,88.22t/data=!3m7!1e1!3m5!1skz8ehpNeEEa-p1mEgJwRAA!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D1.7755842578916088%26panoid%3Dkz8ehpNeEEa-p1mEgJwRAA%26yaw%3D118.84988988489903!7i16384!8i8192?entry=ttu&g_ep=EgoyMDI1MDgxMi4wIKXMDSoASAFQAw%3D%3D) before Exit 305. Southbound between those two points before, it is 75 MPH (https://www.google.com/maps/@46.1352879,-67.7977783,3a,28.5y,305.3h,88.74t/data=!3m7!1e1!3m5!1sV57QGQiphpsFiu_zkVCObw!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D1.2596778474863157%26panoid%3DV57QGQiphpsFiu_zkVCObw%26yaw%3D305.3011432126827!7i16384!8i8192?entry=ttu&g_ep=EgoyMDI1MDgxMi4wIKXMDSoASAFQAw%3D%3D) after the Exit 305 on-ramp.
The Spaulding Turnpike connector in Rochester, NH carrying US 202 and NH 11 between NH 16/Spaulding Turnpike and NH 125 is 40 MPH (https://www.google.com/maps/@43.3292288,-70.9768878,3a,25.1y,251.96h,87.01t/data=!3m7!1e1!3m5!1sKZLIwlzgbm1f6D3KrvxDgA!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D2.9928474726916363%26panoid%3DKZLIwlzgbm1f6D3KrvxDgA%26yaw%3D251.95546754604385!7i16384!8i8192?entry=ttu&g_ep=EgoyMDI1MDgxMi4wIKXMDSoASAFQAw%3D%3D) westbound and 35 MPH (https://www.google.com/maps/@43.3273101,-70.9814732,3a,75y,78.83h,86.2t/data=!3m7!1e1!3m5!1svlOx11xohru37B-ZVpnrxQ!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D3.796540885376544%26panoid%3DvlOx11xohru37B-ZVpnrxQ%26yaw%3D78.82810251543265!7i16384!8i8192?entry=ttu&g_ep=EgoyMDI1MDgxMi4wIKXMDSoASAFQAw%3D%3D) eastbound. I'm guessing EB has a lower limit due to the US 202/NH 11 and NH 125 split ahead after the Turnpike ramps merge.
There was a time when I-93 in Somerville/Boston was posted 45 MPH SB (https://www.google.com/maps/@42.3819085,-71.0767814,3a,75y,185.97h,87.18t/data=!3m8!1e1!3m6!1sVqpz54EZrzNZ9fPfHefPzQ!2e0!5s20150701T000000!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D2.820140785309647%26panoid%3DVqpz54EZrzNZ9fPfHefPzQ%26yaw%3D185.96577424552706!7i13312!8i6656?entry=ttu&g_ep=EgoyMDI1MDgxMi4wIKXMDSoASAFQAw%3D%3D) but 55 MPH NB (https://www.google.com/maps/@42.3669375,-71.0610108,3a,75y,317.66h,94.87t/data=!3m8!1e1!3m6!1sCPgiDQWbU4zs98yF-Z-npw!2e0!5s20150701T000000!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D-4.873878962351171%26panoid%3DCPgiDQWbU4zs98yF-Z-npw%26yaw%3D317.6557951637745!7i13312!8i6656?entry=ttu&g_ep=EgoyMDI1MDgxMi4wIKXMDSoASAFQAw%3D%3D) in July 2015 from Exit 18 SB to the northern part of the Tip O'Neill Tunnel, however, the 45 MPH sign been removed as of July 2016 (https://www.google.com/maps/@42.3818898,-71.0767635,3a,75y,185.97h,87.18t/data=!3m8!1e1!3m6!1skkCJcJ6qWHNW8WmdvmSQsA!2e0!5s20160501T000000!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D2.820140785309647%26panoid%3DkkCJcJ6qWHNW8WmdvmSQsA%26yaw%3D185.96577424552706!7i13312!8i6656?entry=ttu&g_ep=EgoyMDI1MDgxMi4wIKXMDSoASAFQAw%3D%3D) in the SB lanes.
Quote from: DriverDave on June 18, 2025, 11:44:37 PMRead something online recently about roads that have a different speed limit for each direction of the road. Not from construction or there being more/less lanes, but just a different limit for each side. What are some examples of this and what is the reasoning?
It's fairly common in Nevada and, if I remember correctly, in Texas to start lowering speed limits on the way to a {STOP} sign but to put up a reasonable speed as soon as one clears the intersection on the other side. I believe that US-6 goes from 70 MPH down to 55 then 45 then 35 before the STOP sign at NV-360.
US-95 north of Lewiston, ID (the Lewiston Grade) is 65 MPH Northbound (uphill) and 60 MPH Southbound (downhill). I assume it's to discourage drivers, especially trucks, from flying down the hill at unsafe speeds.
Downhill GSV (https://www.google.com/maps/@46.4685451,-117.0292594,3a,75y,128.85h,79.93t/data=!3m7!1e1!3m5!1sJtoYBFFepEnARk9JkH312A!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D10.065199320535882%26panoid%3DJtoYBFFepEnARk9JkH312A%26yaw%3D128.85141140893202!7i16384!8i8192!5m1!1e1?entry=ttu&g_ep=EgoyMDI1MDgxOS4wIKXMDSoASAFQAw%3D%3D)
Uphill GSV (https://www.google.com/maps/@46.4376215,-116.9868527,3a,75y,50.64h,90.76t/data=!3m7!1e1!3m5!1sJvnwvbsXtozc9v3M0iYXRQ!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D-0.7556437557730504%26panoid%3DJvnwvbsXtozc9v3M0iYXRQ%26yaw%3D50.63628751476001!7i16384!8i8192!5m1!1e1?entry=ttu&g_ep=EgoyMDI1MDgxOS4wIKXMDSoASAFQAw%3D%3D)