Parents have been told to act as social distancing "role models" following complaints about crowds outside schools.
Schools across the UK reopened last week with 'bubbles' in place to separate children and limit possible Covid-19 spread.
But one Nottingham mother described the crowding outside her daughter's school as a "death trap".
The scenes have prompted the school to install an extra entrance.
Anna-Marie Dawson, 36, saw the problem first-hand while taking her 10-year-old daughter to Sycamore Academy in Nottingham.
She found the pavement was so crowded she could not get past.
"We had to walk in the road with temporary traffic lights on and we nearly got hit," she said.
"It was rammed and there was no social distancing. There's a bus stop nearby and there's nowhere for them to get off, it's a death trap."
Head teacher Paul Worley said the school was working with parents to make sure its "clear programme" of drop-off and collection arrangements were being followed.
He said: "To further improve the efficiency, we will be installing a fourth entrance gate over the coming days."
Dean Wallace, Derbyshire's director of public health, said it was important parents set a good example.
He said: "Many schools have introduced staggered start times to avoid congestion at the school gates and parents are urged to walk to school where they can, park away from school or arrange a meeting point away from entrances.
"We all need to do our bit to stop the spread and parents and carers need to be a role model for their children by following the social distancing guidance."