All people have only one life and we should be very carefull not to lose it. Therefore, as cars were introduced, the road safety rules appeared. You must remember them and follow them properly:

-When crossing the road with traffic lights, wait for the green light to light and you may go. But even with the green light you should make sure if there's no cars that are going to drive. So look on the left first, then on the right. Made sure? Great, you can go. 

-When travelling in a car, you must always fasten your seat belt. It's done to soften the consequences of possible road accident. Then, you mustn't stick your head out the car window. Some drivers may not notice you and it may even lead to death. And finally, you mustn't interrupt the driver. Even just one touch can be a reason for an accident. So be very carefull.

-Riding a bike has its rules too. If you're riding in on a city road, you have to remember this signals:  hand pointed to the left - you're going to turn left, hand pointed to the right - you're going to turn right, and hand pointed up - you're going to ride straight across the street. If you decided to ride in the evening you must equip lighting on your bike, and have at least simpliest kit with you. 
This is all about basic safety rules. Follow them and everything'll be O.K.