diff --git a/src/transport.f90 b/src/transport.f90
index fe74171..43be999 100644
--- a/src/transport.f90
+++ b/src/transport.f90
@@ -128,6 +128,7 @@ subroutine compute_transport_integral(vmin, vmax, vsteps, D, T)
             ux = ux + du
         end do
 
+        ! Calculate D_plateau (plateau diffusion coefficient)
         D_plateau = pi * vth**3 / (16.0_dp * R0 * iota * (qi * B0 / (mi * c))**2)
         dsdreff = 2.0_dp / a * sqrt(s)  ! TODO: Use exact value instead of this approximation
         D = dsdreff**(-2) * D / D_plateau