You can go by bike EVERYWHERE. There are lots of red bicycle paths and often it's faster to take your bike instead of your car. Many companies offer cheap bikes for students including repairing and exchanging. Nobody wears a helmet although everyone is really fast so pay attention: as a bike-rider as well as a pedestrian! Yesterday a few meters behind me there was an accident because a guy clashed into another one while riding a bike. Fortunately nobody got hurt and both of them could continue going on their way with just a little shock... :-/