JSFiddle - React, Tailwind, and code Playground

HTML

<img src="https://i.imgur.com/2RuqbBc.png" id="bike">
<img src="https://i.imgur.com/VdtpVik.png" id="tardis">

CSS

html, body {
  height: 100%;
}
#bike, #tardis {
  position: absolute;
  top: 0%;
  left: 0%;
}
#tardis {
  left: 90%;
}

JavaScript

let bikePos = 0,
    bikeTo = 80,
    tardisPos = 0,
    tardisTo = 80,
    timerTardis,
    timerBike = setInterval(moveBike, 40)



function moveBike() {
  bike.style.left = ++bikePos + '%'
  if (bikePos > bikeTo) {
    clearInterval(timerBike)
    timerTardis = timerBike = setInterval(moveTardis, 40)
  }
}

function moveTardis() {
  tardis.style.top = ++tardisPos + '%'
  if (tardisPos > tardisTo) {
    clearInterval(timerTardis)
  }
}