buy them...M-F or AAE...they should also be adjustable...not an easy DIY.
if looking for an eagle scout type project that is track related consider...
a "named" planter at the entrance to the track (attract a
donor for improvements to the track!)I'll send you CAD
details for this if you'd like.
or a new formal entrance to the track/stadium. Track stadiums generally lack architectural drama on the approach for the spectator. Could be as simple as a few hedge rows with some low masonry walls.
or help install conduit/cable runs from the 200m and 100m start to the finish for FAT.