I presume these lines are shown on the construction documents(?) As such, they have to be defined somewhere in the construction documents. If the lines are not carefully defined in the documents, yours is a wise question and the Contract Administrator (or whoever)owes you an answer.

I've had many a contractor kick off a project without understanding the basics and, you know the rest.

Bob

perhaps more to the OP

design centerline is typically the crown of the road at the center

construction line is a layout line used for construction. Surveyors stake this line and stake offsets to the line for curb, gutter, crown, etc. It can be anywhere close to the road and it may or may not be at the center of the road.

Thank you for the great explanation.

This would also be a common thing in divided highways. Terminology may vary. Here, I have seen a "Construction Baseline" which may typically be the center of right-of-way (but may be another alignment) - then there is the roadway centerlines. The roadway centerlines may or may not be parrallel with the construction baseline and the may have different curve data and centers.

I wouldn't be afraid to ask that question during the kickoff meeting, or off to the side as the meeting continues. I have been surprised at what certain terminology means to others. Seems better to be on the same page before construction starts.

B+W Engineering and Design
Los Angeles Civil Engineer and Structural Engineer
http://bwengr.com

it would be wise to discuss this in the kick-off meeting just so that you all have the same understanding of what it is (even if it is different definition on another project) contractors tend to have different names for the same thing, especially now days with people travelling all over the world for work

Job specifications should have an apendix describing terminology for the specific project. If not, like said above it wouldn't hurt at all to ask the question. There are no stupid questions related to construction.