The Labour peer and former transport secretary was in the county to give a talk with an Open Britain Shrewsbury group, about the campaign for a people's vote on the final Brexit deal.
He spoke about all things Labour and Brexit, but also had his say on the county's transport.
He travelled to the area from the Labour Party conference in Liverpool, and insisted he had a smooth journey until he hit Shropshire.
He bemoaned the traffic on the A5, and said there is a real need for it to be a dual carriageway, and said he would back any campaign for it to happen.
He said: "I had a good journey down, the traffic was good until I got to Shropshire.
"The A5 wasn't great, and it really should be a dual carriageway.
"I would be an advocate for any campaign that pushed for the road to be dualled, because it does seem an issue.
"It certainly looks as if it needs improving."
Lord Adonis served as transport minister for just under a year.
In that time he said he was pushing for more trains or a through train to be put on between Aberystwyth and Shrewsbury, but said that never happened.
However he still believes better and more frequent trains need to be put in through the county town station.
He added: "When I was the minister the through train was something I was for and tried to push through.
"Even now I still think there is a need for more frequent trains to run out of Shrewsbury.
"I actually visited the station before my talk and it is a fantastic station."