yep tony is right carry straight on at exeter don't turn for the a30 , and the a38 is much quieter it is not till you ar well past the looe turn off, where there is always a tiny build up and the big big build up is where A30 joins the A38 nightmare,!!
Glad everyone goes the A30 way makes it easier for us from plymouth to go cornwall!!!!!,it is more up and down but all dual carriage way as well,Up to the truelfoot round about and turn left there is a big cafe on left called windyridge use to be a huge truck stop but now more cars than trucks,!!!
Have a good trip