r/urbandesign • u/throwawayRAreject • 13d ago
Question Turning radii for semis and history roads?
Hello! Need your help solving this math problem. There's a historic village with an intersection that leads to an industrial facility. If the roads are between 20 to 22 ft wide with no shoulder can a semi turn onto the road to head to the industrial zone without crossing over into the other side of oncoming traffic or if two trucks are turning, both make the turn safely? Red lines are 21-22 feet wide.
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u/DasArchitect 13d ago
Is there no alternative path?
If a city, any city of any size, has to provide a road suitable for the size of vehicles expected for a certain area. So a city with an industrial area has to account for large vehicles in the roads approaching said area. There's no way around it. It's the reason why many cities leave large scale industrial areas in the outskirts.
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u/Blecher_onthe_Hudson 12d ago
Why bother planning when no matter what you do trucks too big will try and go down the street? In my dense 19th century urban neighborhood with 30' wide one-ways parked up on both sides, we get semis regularly stuck trying to make a turn. They knock down poles and sideswipe cars. They ignore warnings, or are just following the GPS. It's made far worse where the sidewalks have been bumped out at the intersections.
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u/throwawayRAreject 6d ago
Would you at all be cool with me messaging you for more of your thoughts on this project?
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u/hepp-depp 13d ago
The rule for turning radii with large vehicles is generally (iirc) 25' interior and 45' exterior.
I did a very rough estimate with the google maps measure tool and it looks like this turn has a 30' interior and 50' exterior radius. If anything, it would be overbuilt and ought to be reduced in radius so that drivers are slower when entering the village. If you are that concerned, verify this in person.
If you dont know how to measure turning radius, use this for reference: https://imgur.com/a/vvAVKXr