If I am right this is a piece that is being taken for eminent domain. There are a few property owners in your nieghborhood that would like to see a sound wall built and the average price is around $3.50 to $4.00 per square foot that is being offered from what I have been told by others along Cajon Blvd.
Hope this helps
Appraisals by Cheryl
That works out to just about $1 per sq ft.
You also need to consider the affect on your lot in regards to resale after the lot line adjustment is made.
Im here if you need anything....