Route Planning for Demand Responsive Transport

Planning Passenger Transportation is more demanding

Passenger transportation that is not covered by scheduled bus routes; also known as Demand Responsive Transport can be both school busses, paratransit, medical trips and more.

A request for transport will, in this field, consist of both a pickup and a delivery. In the morning a student is picked up at her home address and brought to her school, institution or perhaps a treatment facility. Later, the same day, the same transport is often carried out in reverse order.

At first glance one may consider scheduling drive orders like this as assigning pickups and deliveries to every bus in the fleet so that each bus will do as little driving as possible.

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However, in real life there is a number of considerations that the planner needs to do; how many minutes is passenger X allowed to travel, are passengers X and Z allowed to travel in the same bus at the same time or is there enough space in bus no. 58 to pick up passenger Y and his wheelchair at location 79?

Rapidis offer an edition of the Logistics Planner software dedicated to route planning and scheduling in Demand Responsive Transport.

Travel time for each passenger is minimized

Most municipalities and agencies offering demand responsive transport to citizens have strict rules for how the service level should be. A great example is limitations to the travel time for a passenger. Rapidis Logistics Planner will route plan a fleet of busses making sure that no passengers will spend more time in the bus than allowed. The limit can either be a fixed number of minutes or it could be defined as the direct path (if the bus drives the passenger from A to B with any other stops in between) with an addition of an arbitrary number of minutes.

Every single minute that a passenger travels is regarded a cost in the Rapidis Algorithm making sure that travel time for each passenger is kept as low as possible.

Advanced use of time windows

A time windows describes the time span in which a pickup or a delivery must take place. Time windows can be used in

a simple way or you may add more complexity if necessary. Let´s imagine that a delivery task has a time window 07.45 – 08.00. You may now decide if it is OK that the bus arrives within the time window or if also all delivery tasks must be completed within the time window.

”Early pickup” and ”late delivery” are both functionalities that help making the trip more convenient for the passengers. If a passenger has an appointment for treatment at 10.00 and a corresponding time window for delivery 09.0 – 10.00 you may want to flag the “late delivery” option to force the Logistics Planner to plan this trip in a way that allows for this passenger to arrive as close to 10.00 as possible and thereby minimizing wait time at the hospital – off course with little or no increase in the total costs of transportation.

Order Groups

Every drive order may also be labeled with an order group.

Order groups are then used to decide what passengers are allowed to be in the bus at the same time and also who are not allowed to ride together.
Usage possibilities are countless, but one example could be a municipality offering transportation to both children going to school and to the elderly going to treatment. In this case the planner can easily keep the two groups apart if so desired. At the same time, it may be of interest for find out how different rules for who can travel together or not, will affect to costs of transportation.

Resource Groups

Passengers assigned to demand responsive transport may need the secure feeling of being transported by a drive known to them. This demand for “fixed driver” is often very difficult to guarantee; any driver has a sick day now then and, like everybody else, drivers also need vacations.

For all these reasons the Logistics Planner works with ”resource groups”. All drivers can be members of different resource groups and a resource group may have as many members as you want. The idea is that any given drive order can demand a driver from a specific resource group. Securing not a specific driver, but at least a “familiar face”. This will make the route planning much more efficient and, at the same time, realistic and fulfilling to the need of the passenger.

Capacities and Load

Demand Responsive Transport is characterized by buses picking up and delivering passengers during the route. Rapidis Logistics Planner will keep track of how the capacity of each bus is utilized at all times. This is important so that each bus actually has available seats and room for wheelchairs etc. when arriving to pick up one or more passengers. Multiple capacities

Download at use case story explaining how the Danish Transportation Authority uses Logistics Planner for daily scheduling and route planning for school bus routes and other demand responsive transport jobs.

Cost elements

Total costs for the transport can consist of the different cost element that can be calibrated making the plan fit most scenarios.

  • Bus drivetime
  • Travel time for each passenger
  • Start costs pr. bus
  • Task time
  • Pickup or delivery outside time window
  • Max travel time violation
  • Using resource outside preferred resource group

Tools to handle special requirements in Demand Responsive Transport

Factors making the transport inconvenient to passengers, can be related to costs. Logistics Planner will keep the inconvenience factors as low as possible.

As an example will the total costs for the transport increase if passengers travel time increases. Therefore a transport plan with little travel will be preferred.
Som et eksempel kan de samlede omkostninger for transportplanen stige i takt med at passagerenes rejsetid stiger. Resultatet bliver, at planer med kort rejsetid vil blive foretrukket.

  • Max travel time allowed
  • Max travel time related to the direct route
  • Every minute of passenger travel time has a cost and will be minimized
  • On route waiting time is minimized
  • Driver breaks requires empty busses
  • Deliveries can be planed as late in the time window as possible
  • Order groups are used to specify if persons can not travel together
  • Persons with identical transportation needs can be treated as one order
Time windows place time constraints on tasks (pickups/deliveries)

  • Each time window has a start time and an end time
  • Optional and scalable tolerance with scalable penalty for task completion outside time window
  • Optional to allow tasks to only start but not end inside time window
  • Late delivery option places task as late as possible in the time window
Using time windows when planning Demand Responsive Transport
Logistics Planner supports 3 different types of breaks.

  • Fixed breaks with empty vehicle at any location
  • Floating breaks will be inserted after specified period of time
  • Idle time breaks allows vehicle to return to depot
Vehicle capacities vs loads for each DRT/paratransit order

  • Each vehicle can have multiple capacities attached (for instance 8 seats for sitting passengers, 3 spaces for passengers in wheelchairs)
  • Every order/trip requires one or more capacities
  • An order/trip could be a single person (seated), a group of persons (seated) or a mixed group passengers (some seated, some requiring wheelchair spaces)
When 2 persons, (brother and sister), have identical transport needs.

Due to the order handling systems, this may result in 2 orders that sometimes can be carried out by 2 different vehicles.

To avoid this, Logistics Planner can detect such orders and handle them internally as a single order with summed up loads and service times.

Planning the transportation for a group of persons from their individual homes to a common institution or event arriving at the same time.

Better plans can be created when taking this information into account.

Logistics Planner handles both common start and end locations.

Order groups are used to specify if persons can not travel together.

Each order can belong to zero, one or more order groups.

3 different types of rules specify the restrictions. Any number of order groups and rules can be used, but once a restriction is incurred between two orders, the two persons cannot travel together.

  • Do not mix outside order group
  • Do not mix with other order group
  • Do not mix inside order group
All pickup- and delivery tasks have a duration.

When more passengers are pickuped or delivered at the same location the following options can be used in Logistics Planner:

  • Duration reduction factor for subsequent tasks at same location
  • Max total duration for multiple tasks at same location
Rapidis Logistics Planner can respect a route that is already defined. Other orders can be allocated to the bus before and after the predefined routes.

  • The fixed route is treated as one long task with FixedTravelTime as the duration
  • Either pickup or delivery can have a time window, but not both
The example shows a fixed travel time order with a time window on the pickup task. The pickup must occur between 04:00 and 04:10 and FixedTravelTime is set to 16 minutes.
Demand Responsive Transport - a fixed route is incorporated in daily planning

More information and downloads

Selected references

  • Fynbus, regional bus authority planning +500.000 trips (in cooperation with Datapower)
  • Roskilde Brand, large municipality fire department performing paratransit (DRT)(In cooperation with our partner SSD – Secure Software Development)
  • Centrum Turist, medical trips and school bus routes for children with special needs for Skanderborg Municipality (in cooperation with our partner Partex Easy@Tour)