I'm working on a road design for a single lane Forest Road. The road has a 14' lane width and the design needs to accomidate a low-boy trailer with a 18' tractor and 36' trailer. When i set my alignment offsets to add curve widening to the inside of the curves, the program treats my assembly as a two lane road, therefore it adds curve widening referencing the 7' lane rather than the entire road. This makes my road much wider than necessary as the critical vehicle is allowed to use the entire road prism for the turns. The widening error is especially noticable in places where the the road has back to back reverse horizontal curves.
Is there a way to fix this?
Thank you,
David Ratliff
Civil Engineer, USFS
Hi David,
Try this to add automatic widening by manually specifying widening parameters
I am having the same struggle. The manual widening feature really limits your options in terms of how AASHTO (or other) criteria is specified for the 2+ lane options.
Instead, I tried allowing for widening "on both sides" using 1 left and 1 right lane, then just deleted one of the two. It's not bad.