It could see fleets paying tolls according to both the time of day and zone in which their vehicles travel, meaning TfL could charge more for journeys made in congested zones at peak times, and less for journeys on freer-flowing streets at quieter times of the day.
Such a system would also open the door for charging discounts or exemptions for 'essential' journeys made by employees who had no alternative but to drive a car or van to carry out their work, although some higher mileage vehicles within the charging zone could arguably pay more to drive in the capital.
In an exclusive interview with Fleet News, Derek Turner, managing director of TfL, said electronic road charging would allow for the introduction of variable charges based on criteria such as the time of day, the location of the vehicle, and the nature of the journey.
He added that electronic road charging would allow TfL to introduce a more sophisticated, less unwieldy traffic management scheme than the system that will underpin the first wave of congestion charging.
The initial congestion charging system scheduled for introduction next February (and depending on the outcome of calls for a judicial review by Westminster City Council which has consistently opposed the scheme) will see the majority of vehicles incur a £5 per day charge.
The scheme will use cameras to read number plates and feed this information to a central database, where the registration plates will be cross-referred with vehicles that have paid their daily congestion fee. Non-payers will be fined.
While robust, the database technology makes it more difficult to fine tune the charge than a system based on electronic charging, thereby complicating the introduction of discounts or scaled charges.
Turner acknowledges the imperfections of this 'rough and ready' system and concedes that it will have a disproportionate impact on drivers, depending on their needs.
In the West End of London, for example, drivers pay up to £5 per hour to park, so a daily fee of £5 to enter the area is not a significant disincentive to drive. However, for a business whose drivers have to enter the charging zone to visit clients, a £5 per day fee is a significant hit to the bottom line.
'The advantage of an electronic system is its flexibility,' said Turner. 'We could decide that certain categories of drivers only pay £1 per day, or others pay more than £5, and we could price some sub-zones differently to others.'
However, TfL cannot proceed down the electronic road charging route until the Government type approves in-car unit technology so that motorists avoid a proliferation of units to cope with charging schemes in different areas of the country.