detrunk

de- +‎ trunk

detrunk (third-person singular simple present detrunks, present participle detrunking, simple past and past participle detrunked)

1. (transitive) To downgrade (a trunk road) to a normal highway.
   • 1994, Great Britain. Parliament. House of Commons, Parliamentary Debates:

     Oban is not a terminus; its routes radiate by sea, rail and road. I put it to the Minister in the strongest possible terms that it would be quite wrong and extremely damaging to proceed with the proposals to detrunk those two roads, which form part of the agreed national Argyll tourist route promoted by the Scottish Office.

   • 2013, Barry Hutton, Planning Sustainable Transport:

     Simultaneously, the Department for Transport detrunked many roads, shifting the responsibility – and the cost – of maintenance and improvement to local authorities […]

• Kundert, trunked