Cars parking on the grass/field

So many cars park on the field, mostly from the school collection & drop off times & nursery times which is 12pm and 5:30pm. It’s not unusual to see 40 cars parked on the field at one time, this is resulting in the grass turning to mud that’s dangerous especially when it rains and the mud gets thrown onto the paths, a lot of elderly residents live in the bungalows and this makes it slippery and unsafe for them walking, especially when they have mobility issues. The problem has been going on a long time and I’ve reported it before to no avail. Something needs to be done to stop inconsiderate people from parking on here.