The DfT wants satnav makers to improve their directions, and also wants them to start providing alternate routes depending on the particular car. In addition to consumer complaints, the DfT is also reacting to increasing incidents of truck drivers getting stranded on narrow country lanes. The 2,000 times it happens each year are estimated to cost £10 million and create 5,000 hours in delays.
The DfT will essentially issue a seal of approval that it wants buyers to look for as a sign of directional quality. We still don't know what they plan to do about drivers who ignore signs that say, "Don't drive down this road," and people who think its OK to ford a river just because the little voice inside their cars says so.