Transport production incurs significant costs which are mainly attributable to the mobilisation of human resources (drivers) and equipment (vehicles). There must be a process for optimising the construction of the offer in order to control costs: this means offering the best ratio between the transport service offering to travellers and its cost.
What’s more, and although the transport offer is a significant contributing factor to the costs, these can be optimised. This optimisation will depend on the organisation of operation and maintenance that will be put in place on the one hand, and on the operating performance allowed by the infrastructures and equipment chosen for the transportation on the other hand.
The passenger transport service offer
These are the specifications of the contract, drawn up by the AOM (mobility organising authorities), which must set the objectives of the operating contract in terms of the transport offer. At the very least, these objectives are reflected in the route itineraries, the bus service hours which define the bus route timetable, the frequency or the target interval for each day and period of the year.
The limits to be respected in the construction of the transport offer
The construction of the transport offer will have to respect a certain number of constraints associated with the running the route (travel time, interval) and the regulations (working conditions of the drivers).
The timetable scheduling, which is the technique used to produce the transport offer and define the vehicle fleet needs, will have to integrate all of these constraints to arrive at the schedules which summarise the production to be provided for a given period (journeys and target mileage, running of cars, characteristics of agent services). The same applies to the staffing, which is an operating method aimed at defining the driver requirements to cover the service offer.
For all these methods and techniques, specific software can be used to significantly optimise the organisation of the operation by taking into account the main parameters (working conditions, length of the route, operating speed, hazards, positioning of the depot, type of day, route load rate depending on the schedule, etc.).
The optimisation issues in the construction of the transport offer
The optimisation issues essentially form part of the mobilisation times of the human and material resources not assigned to passenger services (dead mileage) or lost because the operating speed is too slow. First and foremost, we will therefore make sure that operators are supervised by competent staff and that the operating and maintenance structure is operational, in order to ensure that the transport system is operable and can be maintained.
We can cite in particular, without the list being exhaustive:
Position of the depot(s): this defines the length of the journeys made to reach the end of the bus route. It therefore has a significant impact on driving times and mileage excluding passenger services and therefore fuel consumption.
Commercial speed: it mainly depends on the road layout that allows the buses to flow freely, particularly during peak hours when urban congestion is high (bus lanes, layout of crossroads, etc.). It also depends on the stopping times at bus stops (boarding, alighting, on-board ticket selling). The distance between stops also plays an important role: it should not be too small but it should also provide adequate service to the area.
Organisation of the start of service: this must be effective at the depot and suited to the timetables of the vehicles. Services should start directly on the route in order to avoid dead mileage in certain cases. The organisation in this regard shall ensure that drivers have a vehicle that is “ready to go” (full tank, no obvious problems relating to the equipment and facilities on board) for the start of the service.
Adequate intervals: they must be studied in such a way as to preserve the regularity of the route (absorption of delays) and a rest time for the driver, without however generating unnecessary technical times
