pegar » to get, take
physically getting Pega aquele documento para mim. Get the document for me.
transportation Vamos pegar o ônibus. Let's take the bus.
transportation Pega o metro. Take the metro.
Use PEGAR to describe physically getting something; taking a mode of transportation (car, metro, bus). You can also use LEVAR when talking about transport (you can get or take a bus etc).