Laravel 5 forms: generate fieldv value instead of having user fill in

I am creating a form that has a field that is required (trip_route_name). I want to generate a name for this (say a random number for example) when the form is submited rather than having the user fill out the form. How do I do that? Here is the code for the form:

<div class="form-group">
    <div class="col-md-6">
        {!! Form::label('trip_route_name', 'Trip Route Name') !!}
        {!! Form::text( 'trip_route_name', null, ['class' => 'form-control']) !!}
        <p      id="msg_trip_route_name" class="text-danger">{!! $errors->first('trip_route_name', ':message') !!}</p>
    </div>
</div>

via Chebli Mohamed