[ecomodded]

Because I keep my 5-speed diesel Beetle in low rpm's it is only feasible to glide on the down hill sections and slight declines. My diesel has enough torque to drive in 5th hear at 30 mph @ 1000 rpm's,it has the ability to pick up speed smoothly at that rpm/speed.
If at faster speeds and on a decline I can put it neutral my rpm's drop to a idle and I coast/glide gaining speed or slightly losing speed,usually the former.
at 60 mph my rpm is just under 2000 rpm this is where my car needs help aka a taller fifth gear or another final drive.
it seems pointless to glide when my rpm's are in the low range. (almost always) I about never drive my Beetle over 2000 rpm..

On a side note I do coast on declines even if my rpm's are low to begin with,coasting makes them even lower. So I coast, hmm I'm a coaster, just coasting thru life taken it easy..in the slow lane, Wow sounds boring but to the contrary I find it interesting enough!