rural highway development

[stephen771]

we are adding a decelleration lane to an existing two lane highway. We have to add a 7 ft. shoulder that varies with a transition zone alignment. this runs on both sides. We are leaving the existing road in tact. How ever the existing road grade varies on each side. One side goes down at 2% then shifts and goes up at 2%. The same with the other side. We are trying to create a template that will follow the present surface up or down and not stay with a definite template design, but allow the shoulder to follow present surface rise or fall. This will keep us from having a crown at the spot where the road blends into the shoulder.

 

[Jim6758]

Better make sure that it drains properly or you will be maintaining it quite often.

 

[KRSServices]

In my expeeerience with this type of design and construction, I have found that it may not be practical to develop a template due to drainage issues and land constraints. I would strive to maintain a crossfall of 2% and concentrate and the transition lengths of the acceleration and deceleration lanes. Any water that will flow on the asphalt will eventually cause segregation, ravelling and premature failure if not maintained. I would try to avoid it.