Miss Hall said she was on a coach full of pupils on their way to a school trip to the University of Sheffield when they were forced to take a diversion because of roadworks on Tenter Street.
She said: "We got to the Cathedral and the driver followed the sat nav down Vicar Lane and onto St James' Street where we got stuck because it's so tight and not meant for coaches.
"We kept shunting and trying different things for about 20 minutes. We were holding the traffic up and then this guy helped us manoeuvre and negotiate the road.
"We ended up reversing down the one-way street towards the Cathedral where we managed to turn and get back to facing the right way and back onto the road."
Miss Hall said she wanted to track the man down to thank him for his help.
"I want to find him as he was a really nice guy. We were running late so I was panicking and just said thanks and left. But it would be quite nice to thank him and go for quick drink or send a card to thank him for his efforts.
"He have up a considerable of his day to help us."
She said the man was around 5 ft 10 ins tall, with blonde hair and a stubbly beard.
If you know who the man was call The Star on 0114 2767676, extension 3528 or email [email protected]