Adjusting Alignment Starting Point

[Iceberg]

I have an alignment that I started 0+00 at the entrance to my subdivision. The engineer wants me to adjust the alignment to the centerline of the existing road. How can I extend the alignment to the centerline and give it a negative value. Say it's 30 feet to the centerline so my alignment would read -0+30.00 then start at 0+00 at my entrance.

[cadtag]

i'll presume that the current starting segment is a straight line.

stretch the alignment to the cl of existing road, <<if i care about the actual distance and don't want any numbers to shift, i'll out a circle at my desired distance centered on my known point>> then right click on the alignment and choose alignment properties, on that dial log, pick the Station control Tab, and set the station for the Reference point to be -0+30.

As a general rule, i find i simplest to start my road alignments at the far RoW, and rarely start at a station less than 1+00

[BlackBox]

Just be mindful of the affect that extended crossing alignments will yield when modeling corridor intersections... As an example, this will result in a four quadrant (four-way) intersection in lieu of a two quadrant (T) intersection.

Cheers