confused about LT and RT meaning in stationing coodinates 1

[delagina]

I have a road plan that says Center of ditch, Station 500+30, 50.00' LT
I was told this is the distance from centerline of road to center of ditch but that wouldn't make sense because the road would have to be 100 feet wide.
Unless 50.00' LT doesn't mean 50 feet.
It's consistent on all road plans I have, it's between 50.00' to 60.00' RT or LT.

 

[Lomarandil]

Perhaps the baseline isn't aligned with the CL of road? On bigger roads (highways), I see that from time to time.

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The name is a long story -- just call me Lo.

 

[bridgebuster]

Why would the road have to be 100' feet wide? LT and RT typically are used to provide a distance from the baseline to the item under consideration.

 

[BridgeEI]

Agree with bridgebuster and the definition you were given. Road doesn't have to be 100ft wide. The depth of the ditch compared to the profile of the road is likely why it's 50ft left. Can you post a picture so we can get a better idea?

 

[delagina]

road is definitely not 100' that's why I'm confused with this LT/RT value showing in the plan.
and I'm not only talking about the ditch, other stuff like culvert seem off also.

 

[BridgeEI]

It looks right. If you take the scale from the alignment station tick marks, that's 100' and if you turn that distance perpendicular to the centerline of the road it's ballpark correct.

 

[delagina]

Ok I'll check the other dimensions maybe it's really some really wide road. My bad for not doing that and just looking at the picture.

 

[BridgeEI]

You're good, roadway plans are sometimes difficult to comprehend especially since a lot of labeling is automated. If you have the cross sections that may help clear it up also.

 

[nkrigPE]

It is 50 feet, 60 feet, whatever the measurement is left (LT) or right (RT) from the profile line. Profile line isn't always center of the road. Roadway nomenclature for left and right is typically based on looking up station (low to high).