The Science of Bike-sharing Monday, January 31, 2011
TAU develops a high-tech tool to improve two-wheeled public transportation
The new environmentally-friendly concept of municipal "bike-sharing is
taking over European cities like Paris, and American cities like New York are
also looking into the idea. It allows a subscriber to "borrow" a bike from one
of hundreds of locations in the city, use it, and return it to another location
at the end of the journey. It's good for commuters and for running short
While the idea is gaining speed and subscribers at the 400 locations
around the world where it has been implemented, there have been growing pains —
partly because the projects have been so successful. About seven percent of the
time, users aren't able to return a bike because the station at their journey's
destination is full. And sometimes stations experience bike shortages, causing
frustration with the system.
To solve the problem, Dr. Tal Raviv and Prof. Michal
Tzur of Tel Aviv University's Department of
Industrial Engineering are developing a mathematical model to lead to a software
solution. "These stations are managed imperfectly, based on what the station
managers see. They use their best guesses to move bikes to different locations
around the city using trucks," explains Dr. Raviv. "There is no system for more
scientifically managing the availability of bikes, creating dissatisfaction
among users in popular parts of the city."
Their research was presented in November 2010 at the INFORMS 2010 annual
meeting in Austin, Texas.
Biking with computers
An environmentalist, Dr. Raviv wants to see more cities in America adopt
the bike-sharing system. In Paris alone, there are 1,700 pick-up and drop-off
stations. In New York, there soon might be double or triple that amount, making the management of bike
availability an extremely daunting task.
Dr. Raviv, Prof. Tzur and their students have created a mathematical
model to predict which bike stations should be refilled or emptied — and when
that needs to happen. In small towns with 100 stations, mere manpower can
suffice, they say. But anything more and it's really just a guessing game. A
computer program will be more effective.
The researchers are the first to
tackle bike-sharing system management using mathematical models and are
currently developing a practical algorithmic solution. "Our
research involves devising methods and algorithms to solve the routing and
scheduling problems of the trucks that move fleets, as well as other
operational and design challenges within this system," says Dr. Raviv.
For the built
The benefits of bike-sharing programs in any city are plentiful. They
cut down traffic congestion and alleviate parking shortages; reduce air
pollution and health effects such as asthma and bronchitis; promote fitness;
and enable good complementary public transportation by allowing commuters to
ride from and to train or bus stations.
Because of the low cost of implementing bike-sharing programs, cities
can benefit without significant financial outlay. And in some cities today,
bicycles are also the fastest form of transport during rush hour.
The city of Tel Aviv is
now in the process of deploying a bike sharing system to ease transport around
the city, and improve the quality of life for its residents. Tel Aviv
University research is contributing to this plan, and the results will be used
in a pilot site in Israel
For more transportation news from Tel Aviv University, click here.