Note 13: Tollway Billing

Posted: 11 March 2006

Tollways capture, and bill for, the passage of vehicles in several ways:

Overhead metering points: Entry, exit and transit points are monitored using overhead gantries with cameras to record license plate details, and devices that interrogate vehicles' electronic tags (where present). The gantries' locations allows each vehicle's trip to be calculated based on the combination of electronic tag/licence plate, a bounded time period and the finite number of trips possible on a specific roadway. This allows traffic to be free-flowing without the interruption of toll collection / measurement. CityLink in Melbourne, Australia is an example where this approach is used.

Entry/Exit metering points: The tollway's entry and exit points contain monitoring equipment which registers customers' vehicles entry to and exit from the tollway (possibly using an electronic tag). Customers' tollway journeys (and charges) are calculated by matching entry / exit registrations recorded within a specified time period (allowing for multiple trips within a day). This approach assumes that there are no other access points other than the measured entry / exit points, and trips that start and end at the same tolling point are errors. Separate entry / exit lanes may be allocate to encourage electronic tag use due to improve traffic flow and reduce operational costs. The New Jersey Turnpike is an example where this approach is applied.
Transaction based metering: Bridges are examples where a fixed (transaction) amount is charged 'per crossing'. The characteristics of the transactions are simple to identify since there are a limited number of bridges in any road network, and they act as a natural 'chokepoint' at which billing for related road networks can be collected. FasTrak in San Francisco, USA is an example where bridge crossings are charged as standard transactions.

Other billing observations about tollway networks include:

Centralised network measurement: A relatively small number of measurement locations (overhead gantries, entry / exit points) generate the billable events for all the (tollway) network's services (vehicles). The number of network services is independent of the tollway's physical 'network', and network provisioning (e.g. supply of electronic tags) can be performed as a network-independent activity.
Multiple collection methods: Modern tollways use tags to capture details of vehicle journeys electronically, but, by also using cameras to identify vehicles' licence plate details, charging for vehicles legitimately using the tollway without tags can also be offered. This allows tollway operators to offer occasional customers the use of the tollway with little effort on the part of the operator or customer. CityLink, Melbourne allows occasional customers up to three days after a tollway journey to pay by purchasing a day-pass.
Transaction collation: Measurements by distributed measurement locations are collected centrally and collated to determine the extent of tollway journeys. This approach centralises the intelligence about what makes up a journey, simplifying the measurement processing in the network.
Rich usage information: Tollway journeys present a rich information source that can support time-of-day (peak, off-peak) and day-of-week (workday, weekend, public holiday) pricing. Vehicle details can also help differentiate pricing between cars and trucks, and between residential, taxi, commercial and government market segments.
Broader penalty options: Many tollway operators bill their customers using a prepaid model with automatic deductions from a credit card or bank account. For occasional tollway customers, day-passes purchased before (or after) the fact can pay for journeys made within a defined time period. Tollway operators may choose to levy an additional administrative fee / penalty when registered vehicles use the tollway without their electronic tags. When payment is not made via any of these mechanisms, tollway operators may pass vehicles' licence plate details to government authorities who can use vehicle registration details to send a traffic fine to the vehicles' owners (retaining their privacy - the tollway operator does not need to know who vehicles belong to for a traffic fine to be levied).
Network sharing: Network operators across different jurisdictions can share use of their electronic tags to broaden the appeal to customers whose vehicles who might transit multiple tollways as they travel. Customers can avoid the registration processes for tollways they may never visit again, and tollway operators can collect journey revenues in a cost effective manner with minimal manual intervention. This approach is similar to that used for mobile phones roaming.

Tags: Billing, Tollway, Collection, Provision, Pricing