Storey completed a double with her win in the C5 road race after her success in Friday’s time trial.
Turnham and Hall were victorious in a sprint finish to add to their time trial bronze.
Britain have now won three golds, a silver and two bronzes.
It was an 18th world title for Storey who finished just one hundredth of a second clear of her rivals Anna Harkowska of Poland, Mariela Analia Delgado of Argentina and Samantha Heinrich of the USA.
“World road race champion! Yay!” the 36-year-old tweeted afterwards.
“So chuffed – was a hard race to control being marked by everyone so had to lead the sprint out and it worked!”
Turnham and Hall, who had finished third in their time trial event, had a hard battle but beat Ireland and Spain in a photo finish.