All the interior/exterior dimension numbers are from
- Manufacturer directly or
- Sites like MSN Autos or Edmunds
There was a question in the gm-volt forum about how I got the Leaf & Volt front/rear legroom numbers. I rechecked these number and they are correct.
As to why Volt feels cramped at the back compared to Leaf is an interesting question, given the official numbers. I think it is because - when Leaf front seat is set with zero height (to maximize headroom), you can't put the feet below the front seat and that reduces legroom.