Professor Anthony Yeh: untangling multilevel road networks

5 May 2018

A new system developed by Professor Anthony Yeh Gar-On allows drivers to determine which road level they have just entered.

Multilevel road networks such as flyovers and overpasses help to solve traffic congestion. However, when we drive onto a flyover, GPS-based navigation systems do not always realise that we have entered a different level and continue to give instructions as if we were on the ground level. It usually takes a few minutes for the system to notice and to redirect us to a new route. This can lead to confusion and driver anxiety, making us more prone to accidents.

Professor Anthony Yeh Gar-On (Croucher Senior Research Fellowship 2001) of the University of Hong Kong has developed a smartphone-linked device which compares the inclination angle of a vehicle and the angles of road levels stored in existing transport databases to determine whether a vehicle has entered the ramp of a flyover or is still on ground level.

The system requires an ordinary smartphone, a small onboard diagnostic device and a digital map.

The system requires an ordinary smartphone, a small onboard diagnostic device and a digital map. It notifies drivers instantly with very high accuracy if they mistakenly enter a wrong road level. 

This innovation won a gold medal award at the Geneva International Exhibition of Inventions in April 2018. It is protected by US and international patents, and has generated several academic papers published in international academic journals including IEEE Transactions on Intelligent Transportation Systems.

Yeh is currently discussing with global GIS and vehicle navigation operators including major Chinese operators on potential applications of the system.

Yeh said, “The invention provides an innovative, simple, and inexpensive method to overcome a long-existing vehicle navigation problem that many people have tried to solve.  We will further explore the possibility of its usage in autonomous cars.”

Videos to illustrate the innovation are available here



Professor Anthony Yeh Gar-On is the Chair Professor of the Department of Urban Planning and Design, Faculty of Architecture, The University of Hong Kong. For more than 40 years he has been studying land use and reforms in China, and is a pioneer in the research and development of geographic information systems (GIS) as planning support systems. He is also an expert in the analysis of urban development in Mainland China after the 1978 economic reforms and is the first researcher to integrate case-based reasoning with GIS in urban planning.


To view Professor Yeh’s Croucher profile, please click here.