.container {
    width: 100%;
    height: 100px;
    position: relative;
    background: grey;
    margin-top: 10px;
    margin-bottom: 10px;
}
h1{
    text-align: center;
}
#stoplight{
    background-color: black;
    width: 80px;
    height: 210px;
    margin-left: auto;
    margin-right: auto;
    padding-bottom: 10px;
    padding-top: 10px;
}
.circle {
    height: 60px;
    width: 60px;
    border-radius: 100%;
    border: 5px solid white;
/*    display: none;*/
    background-color: gray;
    margin-left: auto;
    margin-right: auto;
}
#green {
    background-color: green;
}
#yellow {
    background-color: yellow;
}
#red {
    background-color: red;
}
#car1 {
    width: 35px;
    height: 25px;
    position: absolute;
    background: red;
    vertical-align: middle;
}
#car2 {
    width: 35px;
    height: 25px;
    position: absolute;
    background: yellow;
}
#car3 {
    width: 35px;
    height: 25px;
    position: absolute;
    background: blue;
}
#car4 {
    width: 35px;
    height: 25px;
    position: absolute;
    background: green;
}