Force Bootstrap v4 transitions (ignores prefers-reduced-motion media feature)

transitions.css

/*
 * Force Bootstrap v4 transitions
 * (ignores prefers-reduced-motion media feature)
 * https://gist.github.com/robsonsanches/33c6c1bf4dd5cf3c259009775883d1c0
 */

.fade {
	transition:opacity 0.15s linear !important;
}
.collapsing {
	transition:height 0.35s ease !important;
}
.custom-switch .custom-control-label::after {
	transition:background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out,-webkit-transform 0.15s ease-in-out !important;
	transition:transform 0.15s ease-in-out,background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out !important;
	transition:transform 0.15s ease-in-out,background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out,-webkit-transform 0.15s ease-in-out !important;
}
.custom-range::-webkit-slider-thumb {
	transition:background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out !important;
}
.custom-range::-moz-range-thumb {
	transition:background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out !important;
}
.custom-range::-ms-thumb {
	transition:background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out !important;
}
.custom-control-label::before,.custom-file-label,.custom-select {
	transition:background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out !important;
}
.badge {
	transition:color 0.15s ease-in-out,background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out !important;
}
.progress-bar {
	transition:width 0.6s ease !important;
}
.progress-bar-animated {
	-webkit-animation:progress-bar-stripes 1s linear infinite !important;
	animation:progress-bar-stripes 1s linear infinite !important;
}
.modal.fade .modal-dialog {
	transition:-webkit-transform 0.3s ease-out !important;
	transition:transform 0.3s ease-out !important;
	transition:transform 0.3s ease-out,-webkit-transform 0.3s ease-out !important;
}
.carousel-item {
	transition:-webkit-transform 0.6s ease-in-out !important;
	transition:transform 0.6s ease-in-out !important;
	transition:transform 0.6s ease-in-out,-webkit-transform 0.6s ease-in-out !important;
}
.carousel-fade .carousel-item {
    transition-property: opacity !important;
}

.carousel-fade .active.carousel-item-left,
.carousel-fade .active.carousel-item-right {
    transition: 0s 0.6s opacity !important;
}

.carousel-control-prev,.carousel-control-next {
	transition:opacity 0.15s ease !important;
}
.carousel-indicators li {
	transition:opacity 0.6s ease !important;
}
.form-control {
	transition:border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out !important;
}
.btn {
	transition: color 0.15s ease-in-out,background-color 0.15s ease-in-out,border-color 0.15s ease-in-out,box-shadow 0.15s ease-in-out !important;
}

Thank you very much!

Simple solution, set variable:

$enable-prefers-reduced-motion-media-query: false;