How To Set Different Colors For A Linestring Openlayers 5

I have drawn a lineString of the road that a car went through. The car had different speed values during the road. I have stored the values of the speed with the longitude, latitud

Solution 1:

You can use ol.style.FlowLine to display elevation or speed as color along a GPX track.
See example online: https://viglino.github.io/ol-ext/examples/style/map.style.gpxline.html