Alternative Inductive Loop System

Intelligent Highway Solutions, Inc. is developing a new inductive loop system to gather data relevant to traffic flow, and reduce the power required to maintain the system and use a wireless transmitter to transmit the data.

This project presents a battery-less wireless sensor that can be embedded in the road and used to measure traffic flow rate, speed and approximate vehicle weight. Compared to existing inductive loop based traffic sensors, the new sensor is expected to provide increased reliability, easy installation and low maintenance costs. The sensor uses power only for wireless transmission and has ZERO idle power loss. Hence the sensor is expected to be extremely energy efficient. Energy to power this sensor is harvested entirely from the short duration vibrations that results when an automobile passes over the sensor.

A significant portion of the project focuses on developing low power control algorithms that can harvest energy efficiently from the short duration vibrations that result when a vehicle passes over the sensor.

The objective would to use existing sensor technology, existing wireless technology to reduce the development time of this project.

We would expect that once fully developed and tested, the new system would replace traditional inductive loop systems. To install a loop detector and calibrate it, it is sometimes necessary to shut down traffic on the road for as much as 2 days. The new sensors can be installed by drilling a slot across the lane in the road surface of 1 inch width and 2 inches depth. Most importantly, no wiring is needed from the traffic lane to the roadside data acquisition unit. It is expected that the installation will only take a few minutes.

The new sensor on the roadway requires no external power supply while inductive loop detectors have to be continuously powered all the time, even during the night when traffic flow might be really low.