At my DCs' elementary school in the US no parent ever entered the school for drop off or pick up. We waved goodbye outside, they lined up and were admitted class by class at 7.55, led by teachers. The tardy bell rang at 8.03 and if a child was later than that they had to be buzzed in through the office door. Class started at 8.07 promptly. Everyone had to have their coats, hats, scarves, snowboots, snowpants, gloves, etc off and hanging in lockers (cubbies for 4 and 5 yos) by that time. Amazingly, even the smallest children managed to do this without help from parents.
All teachers and the principal guaranteed that they would return phone calls within 24 hours, and e-mails too.
It worked really well from every pov you could imagine - security, ease of transition, parents happy with responsiveness, teachers and principal and office staff all happy not to be waylaid by parents seizing an opportunity to buttonhole.
Parents were welcome to gather to chat on the sidewalk which was right outside the school but conversations could be heard in the classrooms if the windows were open and therefore it didn't happen a lot. People generally drifted off to a local coffee place and of course a lot of parents worked so pulled up and dropped off at the curb and off they went.
This was a private, fee paying school.