GPS: NOT Good for Mass Tracking Cars (Road Congestion Pricing)

GPS is unsuitable for mass tracking of cars, necessary for an effective road pricing scheme. Such schemes have been touted for years as the answer to congestion by many countries. GPS has been around for years, but never used in this context, for many reasons as below:

Power: GPS draws high power to ‘hear’ satellites & process orbit calculations. GPS often runs phones flat quickly with constant location use. Congestion tracking can’t have high-power consumption. Devices are expected to operate self-powered for years. Hard-wiring power means retrofitting millions of vehicles at untenable expense, and can be easily defeated by severing power lines. Mass adoption requires secure self-contained power, like current (legacy) toll transponders mounted on windscreens.

Note: Security tracking is very different to congestion tracking. For security, the device may detect & transmit positions each ten minutes to be effective for its security purpose. Road pricing needs a much higher resolution tracking (billing by km), which consumes far more power than a GPS theft tracker.

Antenna: GPS tracking requires an antenna mounted with line-of-sight to the sky. They mount inside the dashboard or intrusively on windscreens to hear signals. Antennas are an Achilles heel. Drivers can sever the antenna wire, or shield with foil to make the vehicle appear not moving, and thus will not incur congestion road use fees. Even if movement itself is detected via sensors, lack of GPS positions means movement is assumed non-main road use, such as on private property or local roads, so not billed.

Heavy earthmoving equipment can’t use GPS easily due to difficulty placing sensitive antennas. Thieves break antennas or wires to steal vehicles, as GPS antennas can’t be fitted easily or securely internally in a solid metal vehicle due to faint signals being blocked. Such vehicles use wireless or GSM tracking instead, which isn’t as good for position accuracy and has coverage limitations, but is fitted securely.

Retrofit: Positioning technology requiring an external power supply to provide constant power, or a GPS antenna that must be carefully positioned with line-of-sight to sky (e.g. under dashboard, not under the hood) is wholly unsuitable for mass adoption of secure road pricing system. The cost of retrofitting millions of vehicles with expensive tracking hardware would be immense, and also incur liability risks.

It would cause uproar that governments are installing surveillance equipment into vehicles. Drivers will be most unhappy having their vehicles intrusively modified. By being so physically installed, it’s a ‘bigger thing’ than simply placing a small toll transponder on their windscreen and never worrying about it again.

Communication: GPS is point based tracking, requiring several Kb of data to transmit routes. Dynamic road pricing requires high resolution of positions recorded and sent, unlike normal security asset monitoring. They need a solid internal power source. Neomatrix compresses routes so small they can be powered externally (no battery) via RFID like current toll transponders to send a full route history. Neomatrix compresses routes to a few dozen bytes, not several Kb (two orders of magnitude smaller).

For reference, similar new tracking technology Sigfox (Still antenna based) reports: An uplink message has up to 12-bytes payload & takes an average 2s to transmit to the network. This is sufficient to send 2x GPS points at 3m accuracy. By comparison, Neomatrix can send a 30min full route in just 20 bytes!

Security: GPS systems are defeated easily, with lots of internet examples. It’s semi-common practice among some commercial drivers to disable tracking of vehicles or their containers to avoid monitoring. With the need for an ‘accessible’ antenna and power cable, such devices can be very defeated by severing wires, shielding or damaging antennas, or using (illegal) GPS jamming devices which are very cheap, and used regularly. This causes problems - even drone crashes.

At extremes, it’s easy to disable GPS satellites by rouge nations firing ASAT rockets to disrupt economies. GPS Spoofing can also affect wide areas, reported by the BBC as used in Russia.

While unlikely, the more we rely on GPS, it becomes a weak link target. GPS has a place in many contexts, but vulnerabilities in GPS mean it’s not viable for road pricing, when used in millions of cars.

Cost: With millions of vehicles, GPS at scale is expensive, let alone significant installation costs and associated liability. GPS is cheap individually, but not compared to alternative positioning technology such as from Neomatrix which is far cheaper, simpler, and needs no antenna or installation.

Privacy: GPS is not privacy friendly. See next FAQ section

GPS: NOT Privacy Friendly for Road Congestion Pricing (tracking)

Privacy: GPS resolves position to an error of maybe 3m, so it’s high-resolution tracking. It’s an obvious concern for drivers, who feel this is intrusive. The purpose of tracking is solely to detect and price use of main roads at busy / congested times, yet the government is tracking their movements everywhere, anytime, and accurately. It seems an extreme overreach.

The government may say ‘Yes we could track you in private areas, but we promise we won’t do this’ would be endless debate and concern in consumer’s minds that they are entering an Orwellian surveillance state. Drivers don’t want to be tracked when having affairs, spending their work time at the beach, or perhaps even speeding on quiet roads. Even when conducting business normally, drivers will be ‘disconcerted’ knowing they are tracked to such resolution all the time.

Alternative, newer technology addresses privacy in novel ways, with technology that is ‘physically incapable’ of tracking movement, except on main roads, and at known/defined congested peak hour times which is the purpose of the data capture. Drivers will accept privacy implications far better if it’s limited to only the purpose designed, which is a core GDPR data privacy requirement too.

As a thought experiment, the government could easily erect many toll booths across all main roads to implement large scale dynamic road pricing. However, erecting toll booths each km along main roads is cost prohibitive, and visually unsightly. Still, this would not invoke extreme privacy concerns that GPS would. Tracking ‘on’ the car or person is vastly more intrusive than a fixed toll booth tracking a car passing by. Users easily understand the reason for the toll booth tracking, but can’t justify individual car tracking constantly ‘in case’ it may drive along a toll road at some future time.

To address privacy well, monitoring systems should only track cars when actually driving busy main roads, but not to the high resolution of GPS, or to the global coverage area of GPS (everywhere).

Neomatrix positioning can only do main road ‘route tracking’, not point tracking (like GPS), so allows privacy to be addressed by default – as it is only able to monitor movement along main road routes.

Evidence on privacy concerns: A significant UK Government paper called London stalling. Reducing traffic congestion in London includes these comments from David Kurten AM, UKIP Group Lead on the Transport Committee: “The ultimate aspiration for London however is ‘big brother’ style total vehicle monitoring for the entire Greater London area. All vehicle movements would be monitored and charged by a government agency: probably TfL. This will destroy privacy & civil liberties for motorists in London.

Comments above show an (incorrect) understanding that vehicle monitoring must be ‘all vehicle movements’, meaning point based (GPS). Route based tracking is very different, and almost an extension on more toll roads, but without needing any toll gantries.

Privacy is addressed by a radical shift in how we monitor cars. Existing tracking systems are ‘Big Brother’ and cover ‘entire areas’, when this isn’t needed if a new system can only physically monitor main road driving. Route tracking is also technically unable to identify end points of journeys, as they are not ‘a route’, being another benefit for privacy over GPS which has no difficulty knowing exact end addresses.

Automated Number Plate Recognition NOT Good for Road Tolls

Video camera plate surveillance is an alternative to using toll transponders and toll booth gantries to detect vehicle toll tags. It is extremely expensive to install cameras, which means they can't cover all main roads effectively. It is also somewhat onerous for privacy concerns.

The recent London report on congestion as clearly stated that automated number plate recognition was dated, and that new technology to monitor vehicle use was needed.

Toll tags NOT Good for Road Tolls

For road pricing, vehicles must be monitored. Studies consistently advise that vehicles should be monitored per km and per time through main roads. Toll booths, automatic number plate recognition and congestion zones are regarded as 'Not fit for purpose' according to a recent and extensive government report on congestion in London. This report states that new monitoring technology for vehicles is needed to support road pricing effectively.

Retrofitting millions of existing vehicles is very expensive, and will have significant push back. Owners don't want government 'surveillance' hardware installed into their vehicles. Questions will be raised if this device records conversation for example. Issues of liability, who pays for the power, depreciating car value, damage, installer accreditation and so much more. In short it would be a PR nightmare to sell an installed tracking system to a city.

Road pricing should focus on small, cheap, removable devices that do not require installation or vehicle power. The public are happy to install a toll transponder on their windshield.

Neomatrix technology can be used in the same way, with smart toll transponders that detect position without toll booth gantries.

NeoTag: Route Compression

Neomatrix has developed a novel and useful method of highly compressing route information. This compresses a series of GPS points to a NeoTag, which is just a few characters. Compression rates of 99% are possible, yet the few characters in a NeoTag can be decompressed to reveal the exact route, including timestamps. Routes are not stored in a separate database, they are stored within the tag itself.

There are many reasons such compression is helpful, but the primary use case is for road pricing. Smart number plates or toll transponders may need to communicate a historical route taken, so use of congested roads at peak times can be sent to the toll authorities for billing.

In this context, there are very tiny batteries, as these devices can't be hard wired to vehicles for security, cost and other reasons.

NeoTags are so incredibly tiny, which is helpful for a small battery powered monitoring device to send just a few characters to communicate a lot of driving. Also, connection windows are also tiny, as vehicles speed under toll booth stations - and can't be paused to complete a longer transmission.

The NeoTag method is somewhat technical, but is perfectly designed for road pricing schemes which is what it was specifically developed for. The NeoTag method and use in smart number plates etc for road pricing schemes is subject to a pending patent application.

Accuracy of Neotag Compression

NeoTag is a compression format. Accuracy for positional information is retained 100%, however this is based on the snap-to-road positions, which is a very common processing technique. In almost all cases this provides higher accuracy than original source data for recording position, as it actually corrects most GPS errors. With this caveat, the NeoTag is lossless for compressing the corrected paths.

NeoTag accuracy for time information is lossy. This accuracy is configurable, with the highest being one minute accuracy, though the default is five minutes. So it can detect the time a vehicle was anywhere but not 'to the second' accuracy as may be driven or recorded by GPS originally.

Most use cases for recorded route information do not require such high resolution accuracy as per-second. To answer questions of what time was a delivery made, or what time did a worker leave a job, five minute accuracy is quite adequate, and noting this is a maximum error - the average will be much lower.

Additionally, human error in recording time manually (and slight errors in the time on watches etc) would be expected and accepted as within a few minutes. It is expensive in tag 'space' to record to per-second accuracy, and in most cases unnecessary.

For detecting speeding, the method records timestamps that can easily be used to identify significant speeding events, so long as they are not isolated like a relatively brief high speed overtaking maneuver. Any prolonged speeding would still be able to be determined from the compressed format, while privacy concerns can be reduced if isolated brief speeding isn't being captured or retained in the NeoTag format.

Accuracy of Neomatrix Tracking?

GPS works by trilateration of distance to three or more satellites, resulting in a 'triangle of error', where the position is determined to be in the centre of this triangle (10m error perhaps).

Neomatrix is not a point tracking system but a route tracking system. The error profile of the position is very different. In some cases the positional accuracy will be higher than GPS, and can be provided in areas GPS can't work - e.g. tunnels. But in other cases, it may be less clear. The area of error may be 500m or even more in extreme cases.

Provided the system is able to monitor movement in an ongoing manner as designed, it can provide reasonably high accuracy with confidence. Note that error reduces once the device moves onward, such that live error may be worse than historical error. Subsequent movement 'corrects' previously detected positions.

Speeding Privacy: Route Tracking (vs GPS)

GPS is a point tracking system and provides high accuracy, high resolution data on vehicle speed. This is frequently used by fleet managers and parents to take action against offenders.

For mass adoption of a road pricing scheme, the new ability of authorities to instantly detect all instances of speeding with accuracy is a worrying concern for big brother. Speeding isn't a factor in causing road congestion, and indeed while illegal, it could even be seen as helpful for reducing time spent on roads. Strategies to reduce congestion should not be confused with, or integrated with initiatives to address speeding.

With the public sensitive to big brother privacy, 'mass surveillance' of citizens for purposes of reducing congestion - such systems need to take great care they don't bleed into areas they were not originally designed for.

Because Neomatrix isn't a point based tracking system, it simply can't be used for this in the same way as GPS. It can't reliably detect isolated instances of speeding. Additionally, it can't detect low level speeding in metro areas. The monitoring method simply can't 'see' these events clearly. Only prolonged speeding can be detected, exactly how point-to-point speeding cameras work. The public seem more comfortable with these schemes than being caught at a specific 'point', and want the ability to e.g. speed in order to overtake, but not necessarily have this detected as an offence.

The Neomatrix positioning technology can't detect speeding easily unless prolonged, but also, the NeoTag format smooths out speeding as part of its compression method. The data received from smart number plates by road authorities is thus even more broad, with individual and isolated speeding not seen clearly to begin, and also further smoothed if it is detected.

The end result is that unlike a point tracking system like GPS, Neomatrix positioning directly addresses privacy concerns on speeding detection. The system can be used to detect speeding but only in limited cases of extensive or prolonged speeding, and is far less likely to detect speeding in metro areas due to the smoothing methods. The public may be more accepting of this use case, but essentially, the system is designed to reduce traffic congestion, not to be used as a big brother surveillance tool, such as mass speeding detection. That it can't be used effectively for such surveillance should offer some comfort.

Presenting Road Pricing to Cities

While technical aspects of road pricing are a significant barrier to adoption in monitoring positions, consumer acceptance is also a big a hurdle to address.

The privacy aspects are critical. GPS and any point tracking system is highly invasive for privacy. Consumers don't want to be tracked 24/7 or to high resolution. They don't want to be detected occasionally speeding, and they don't want their final destinations tracked.

Neomatrix addresses these concerns. By only being able to effectively track main road use, being unable to track final stop destinations accurately, and being unable to detect speeding unless sustained … Neomatrix gives privacy confidence.

How a scheme is described is critical. Language is key. Sell the benefits, not features.

Negative terms: Congestion tax, road tax, road pricing, road tolls..

Positive terms: Road pass. Peak hour passes. Fast Lane pass. Speed passes..

We are 'selling' he opportunity to travel at peak hour faster than now. Road pricing reduces congestion - so consumers are buying time, and thus traversing the network faster.

The word tax implies a sunk cost. We may not see benefits of this directly, and not as an individual. A road fast pass however, seems to offer a direct and individual benefit to the driver. They are paying to get somewhere faster. They get something for their money.

What is traffic congestion?

Traffic congestion is what occurs when too many cars try to use a road, such that they approach it’s maximum capacity. It results in far slower speeds, travel times, costs and pollution. The efficiency of the road network is also non-linear, such that roads can accommodate a lot of traffic, but above a certain point close to the maximum capacity, congestion occurs and slows everything down significantly. Strategies to keep roads at good capacity but with some room to move help to keep traffic flowing more efficiently.

Point Tracking vs Route Tracking

GPS is a point tracking service, resolving position to a specific given point, anywhere on the surface of the world, to a very high accuracy of generally less than 10m. This can be regarded as highly intrusive from a privacy perspective, as there is no escape. The system, if active, can identify exactly where you are, all of the time, to an incredible accuracy. This is highly effective for many applications, but is also highly intrusive from a privacy perspective, if users are tracked in this manner when they don’t need to be. In general, GPS is often regarded as a live system. Once a point is resolved, it can be immediately transmitted to a recording station.

Neomatrix is NOT a point tracking system. It is unable to directly identify points, but rather, it identifies routes. This is a very significant difference, and in particular addresses a number of privacy concerns in an elegant manner. Because it only works through comparing sensor data to known routes, there can be direct and simple transparency of which routes are ‘permitted’ to be identified. This is perfect for congestion pricing, where only main roads need to be included for tracking. This means that unlike GPS, the system can’t resolve users' positions anywhere other than when driving along main roads - which is what is needed for road pricing to be effective.

Congestion Keeps Growing (Ridesharing / Home Delivery)

City centres are becoming increasingly clogged with ride sharing vehicles, due to their low cost and convenience. People adopt ridesharing more now than public transport, due to their low cost convenience. Delivery vehicles are also increasing rapidly, as online shopping becomes the norm. A smaller factor is the natural increase in the city population over time.

While some may doubt, most agree we are on the cusp of realising self driving vehicles. Many expect these to begin being available within a year or two. Reports advise the floodgates will open as there is a massive shift to driverless fleets. Tesla for example has lease agreements that prohibit the lease owner from buying the car at the end of the lease. Tesla still sells cars, but is reserving the right to retain their entire lease fleet, as they have indicated driverless ride sharing is far more valuable than sales of cars outright.

The impact of driverless ride sharing vehicles has an ominous, looming impact for traffic congestion. With no driver’s wage to pay for, the cost of a driverless rideshare vehicle will be a fraction of current costs. Some estimates put the driver’s wage as 80% of the cost of the transport, meaning we could see ridesharing costs plummet to less than a third of current costs.


The seismic collapse of ridesharing costs will almost overnight result in a massive increase in demand for such services. There is a strong incentive for self driving vehicles to be on the road 24/7, as the cost to run these electric vehicles without a driver is just pennies to the owner. Sadly, the cost to the city is not pennies. In London, the current cost of traffic congestion is now £8 billion per annum (USD $10 Billion). With self driving ride sharing vehicles pouring into the network as fast as they can be built, this figure will sharply increase.

The USA’s Union of Concerned Scientists is a large professional body, dedicated to scientific research and reporting on big problems. ucsusa.org/sites/default/files/2020-02/Ride-Hailing%27s-Climate-Risks.pdf

This report states: A typical ride-hailing trip is about 69 percent more polluting than the trips it replaces, and can increase congestion during peak periods