枠外から中央で一時停止→反対側へ走り去るCSS

<div class="car_wrap">
    <p class="car">車</p>
</div>

.car_wrap{
    height: 50px;
    position: relative;
	overflow: hidden;
}

.car_wrap .car{
    position: absolute;
    left: -20%;
    animation: carAnime 6s ease-in-out infinite;
}

@keyframes carAnime{
    0%{left: -20%;}
    30%{left: 47%;}
    60%{left: 47%;}
    100%{left: 120%;}
}