Bang on schedule!



Consider a company renting different types of recreational vehicles to customers from locations over a vast geographical area. A customer books a vehicle specifying the pick-up and drop-off points as well as preferred times for both. The booking also specifies the type of vehicle required and possible substitutes if the vehicle of choice is not available.

If the requested vehicle is not available at the specified location and time, the company needs to move it from another location. Such a transfer is called ‘relocation’ and comes with a cost. The another option is ‘substitution’, where a different type of vehicle is assigned to the customer. This, too, comes with a penalty cost. For a recreational rental company, a significant amount of the operational cost consists of costs due to relocations and substitutions. An effective management of relocations and substitutions of the vehicles helps in reducing the overall operational cost, which in turn reflects in the price paid by the customer.

Finding the best combination of the relocation and substitutions (out of billions) is a very difficult task, This is precisely where Sarang Kulkarni, a research scholar with the IITB-Monash Research Academy, is hoping to make a mark. He is working on a project titled ‘Recreational vehicle scheduling: flow routing problems on a time-expanded network’ under the supervision of Professors Mohan Krishnamoorthy, Rahul Patil, Andreas Ernst, and Abhiram Ranade.

Fig 1: Different types of recreational vehicles (Source: www.


The Academy is a collaboration between India and Australia that endeavors to strengthen scientific relationships between the two countries, and graduate research scholars like Sarang study for a dually-badged PhD from both IIT Bombay and Monash University, spending time at both institutions to enrich their research experience.

A good vehicle schedule not only reduces the overall operational cost but also helps in the daily planning of the activities like maintenance and answering the reservation inquiries. The schedule also helps the company in accepting a new booking request with a high degree of certainty thereby improving customer satisfaction.

“Given the information regarding accepted bookings and availability of vehicles at a given point of time,” says Sarang, “the challenge is to prepare a schedule for each vehicle in the fleet, for the entire planning horizon, by deciding on suitable relocations and substitutions, in order to reduce the total cost of relocation and substitution.”

Fig. 2. Parking of RVs at one of the company location (source:


He hopes that his research will help offer solutions to not just recreational car rentals, but other similar domains like the airline industry, public-transfer system, shipping, and manufacturing, where automated vehicles need to be scheduled based on demand.

Explaining his work so far, Sarang says, “At present, we have been able to find an approach that can produce solutions with a reasonable amount of time for large-sized problem instances that are provided by the industry. The new formulation works well with the standard solvers. Using the standard solver alone, we have been able to find solutions to large-sized problem instances for which other existing formulations have struggled. We need to refine this now.”

Prof Murali Sastry, CEO of the IITB-Monash Research Academy, is reasonably confident that he will succeed. “The IITB-Monash Research Academy is an opportunity for the industry in Australia and India, as well as for IIT Bombay and Monash University, to train the next generation of rich talent in India. The ‘Academy’, therefore, has the potential to be a significant research institution. Talent from the Academy should become much sought after around the globe,” he emphasises.

Sarang Kulkarni couldn’t agree more.

Research scholar: Sarang Kulkarni, IITB-Monash Research Academy

Project title: Recreational vehicle scheduling: flow routing problems on a time-expanded network

Supervisors: Prof Mohan Krishnamoorthy, Prof Rahul Patil, Prof Andreas Ernst, Prof Abhiram Ranade

Contact details:

This story was written by Mr Krishna Warrier based on inputs from the research student, his supervisors and IITB-Monash Research Academy. Copyright IITB-Monash Research Academy.