Scattermapbox doesn't show any symbol for points with size value = 0

📊 Plotly Python
1

for this application i need points with a value of 0 to to still appear as markers on the map (and preferably in a different color that isn’t on the color ramp, like black). is this possible with scattermapbox

    fig = px.scatter_mapbox(buses_gdf,
                            lat=buses_gdf.geometry.y,
                            lon=buses_gdf.geometry.x,
                            size='passengers',
                            # todo how to make the buses with zero passengers appear?
                            size_max=30,
                            color='passengers',
                            # color_continuous_scale=['#23bf06','#e55e5e'],
                            color_continuous_scale=[(0, "black"), (0.5, "green"), (1, "red")],
                            hover_name="lineref",
                            hover_data=["trip_id",
                                        "vehicleref",
                                        "next_stop_id",
                                        "next_stop_eta",
                                        "next_stop_d_along_route",
                                        "next_stop_d"],
                            # todo write labels for rest of hover fields
                            labels={
                                'trip_id':'GTFS Trip Identifier'
                            },
                            opacity=0.8,
                            zoom=11)