Per trip price per kilometre

Add a way to show and compare price per kilometre when you specify the price from the create trip page. Some journeys, such as a bus, don't require the complexity of creating a ticket, however if you just specify the price for the trip you lose the ability to view the per km stats and compare it. Ideally this might just show trips with a price attached to them in the ticket list, or another, page, allowing comparison with tickets created as well.