Cell Phones and Radioactive Imaging – Measuring Flow

Stuck in traffic a few days back, my idle mind wandered to thetechnical feasibility of pervasive, real-time trafficflow monitoring, and how this information could be communicated andutilized.

Such perfect, real-time information could help to redistributethe roadway load for the benefit of all (or, more realistically,let the suckers boil in the midday sun while the informationinsiders zip around congestion points), reducing transit times andenergy use, and perhaps providing emergency services with optimizedtransport mapping, improving their efficacy.

Something had to be better than the sparse, time-laggedreporting of the radio station, or blindly rolling down an onramp,curious why a string of cars were dangerously reversing up theshoulder, to find the entire highway at a standstill, as I had thatFriday afternoon.

There are quite a few implementation options apparent to atraffic layman like myself: Cameras with AI counting cars andestimating their speed. Underground (or overhead) magnetic sensors,or underground weight sensors. Laser relays for single laneroads.

The basic problem with such solutions, however, is that theytend to be expensive to install and maintain, and from that theytend to be infrequently deployed, at best spaced at distances thatgreatly reduce their utility (e.g. “between highway marker 70 and112 there is some sort of disturbance”). Add to that thecommunications network required to relay these telemetrics.

Having worked in the telemetrics/remote monitoring industrybefore (in the late-90s), I was contemplating how cellular datatechnologies were just become feasible for such remote monitoringcommunications when the thought occurred to me: Most every cellphone now is constantly communicating digitally with its basestation. Further, every cell phone can be either triangulated to alocation, or more recently knows its precise position with the useof GPS. A tremendous percentage of cars on the road have at leastone cell phone in them, the phone company (or anyone listening inon the conversation) capable of tracking location and speed, easilyoverlaying that over a mapping system to determine roadwayflow.

Imagine an entire roadway system that overlaid the millions ofcell phones moving around, easily visualization slow downs andcongestion. It would be similar to the medical procedure wherethey inject radioactive particles into a patient’s blood system,determining flow throughout the body by measuring theirmovement.

It turns out that I’m not the first to think of this. A quickGoogle search upon getting home made it apparent that there areseveral commercial products that do something similar. NonethelessI thought it a fascinating example of passive data collection,deriving secondary advantages out of widely deployed technologieslike cell phones.