Traffic, Saint Petersburg
As all large cities St Petersburg has loads of traffic, so use the crossings , believe me the green man will come on. The Metro gets very crowded, watch out for pickpockets. Saturday and Sunday seems less busy.
More an annoyance than a danger: There is heavy traffic on the Newsky Prospekt, it is very loud 24 hours a day, and sometimes you have to catch your breath due to the the car fumes. If you have a hotel next to the Newsky prospekt, you will have to live with it. Apart from that, Newsky Prospekt is a fascinating place.